# TaxSessionsPublicController_Amend

Creates an amended tax session with an incremented Sequence.

`POST /api/v1/TaxSessions/Amend`

**API:** Excise Platform API
**Tag:** Tax Sessions
**API Version:** v1
**Base URL:** https://excise.avalara.com
**Accepts:** `application/json`
**Authentication:** Basic (username + license key)

Source: https://developer.avalara.com/products/excise/api/methods/Tax%20Sessions/TaxSessionsPublicController_Amend/

## Description

Creates an amended version of the specified tax session with an incremented Sequence number.
The highest sequence must be filed before an amendment can be created. The new sequence
inherits settings from the previous sequence. The amendment type is set to "AMENDED".

## Parameters

| Name | Type | In | Required | Description |
|---|---|---|---|---|
| `x-company-id` | integer | header | Yes | Company ID that owns the data. |
| `X-Avalara-Client` | string | header | No | Identifies the software you are using to call this API. For more information on the client header, see Client Headers. |
| `headerId` | integer | query | Yes | The header id of the tax session to amend. |

## Responses

| Status | Description | Schema |
|---|---|---|
| 200 | Returns the newly created amended tax session details. | `Avalara.Excise.Common.Contracts.Services.RestTaxSessionResponse` |
| 400 | The HeaderId is invalid or the highest sequence is not filed. |  |
| 401 | Authentication credentials are incorrect. |  |

### 200 Response: `Avalara.Excise.Common.Contracts.Services.RestTaxSessionResponse`

Response returned by Tax Session Create, GetByHeader, and Amend endpoints.

| Property | Type | Required | Description |
|---|---|---|---|
| `CompanyName` | string | No | The company name. Example: `Acme Fuel Co`. |
| `CompanyId` | integer | No | The company context under which the session was created. Example: `100`. |
| `HeaderId` | integer | No | The unique header identifier. Example: `12345`. |
| `Country` | string | No | The ISO 3166-1 alpha-3 country code. Example: `USA`. |
| `Jurisdiction` | string | No | The jurisdiction or state code. Example: `AL`. |
| `TaxpayerType` | string | No | The taxpayer type code. Example: `DIST`. |
| `TaxpayerDescription` | string | No | The human-readable taxpayer type description. Example: `Distributor`. |
| `TerminalCode` | string | No | The terminal or facility code. Example: `T01ME1000`. |
| `TrackingNumber` | string | No | The tracking number. Example: `TRK-2024-001`. |
| `LocationID` | integer | No | The location identifier. Example: `501`. |
| `ReturnCode` | string | No | The return code. Example: `RET-001`. |
| `ReturnEffectiveDate` | string | No | The effective date used for determining applicable return rules and rates. Example: `2024-01-01T00:00:00`. |
| `StartDate` | string | No | The first day of the reporting period. Example: `2024-01-01T00:00:00`. |
| `Sequence` | integer | No | The sequence number (0 = original, 1+ = amendments). Example: `0`. |
| `EndDate` | string | No | The last day of the reporting period. Example: `2024-01-31T00:00:00`. |
| `DueDate` | string | No | The due date for filing the return. Example: `2024-02-28T00:00:00`. |
| `FiledDate` | string | No | The date the return was filed, or null if not yet filed. Example: `2024-02-15T00:00:00`. |
| `PurgedDate` | string | No | The date the session was purged, or null if not purged. Example: `2026-05-22T04:06:19.0187470Z`. |
| `CriticalScheduleErrors` | integer | No | The count of critical schedule-level errors. Example: `0`. |
| `ReturnGenerationNeeded` | boolean | No | Whether the return needs to be regenerated. Example: `false`. |
| `ReturnStatus` | string | No | The calculation status of the return. Example: `Calculated`. |
| `FrequencyType` | string | No | The filing frequency description (e.g. Monthly, Quarterly, Annual). Example: `M - Monthly`. |
| `FrequencyTypeInd` | string | No | The filing frequency indicator character. Example: `M`. |
| `SessionSourceInd` | string | No | The session source indicator character. Example: `M`. |
| `SessionSource` | string | No | The human-readable session source description. Example: `Manual`. |
| `SessionLocked` | boolean | No | Whether the session is locked from editing. Example: `false`. |
| `PurgeExcludeInd` | boolean | No | The purge-exclude indicator. Example: `false`. |
| `PreventArchiveandPurge` | boolean | No | Whether archive and purge is prevented. Example: `false`. |
| `ReturnPdfSegmentCount` | integer | No | The number of PDF segments generated for the return. Example: `0`. |
| `GLReconGenerationNeeded` | boolean | No | Whether GL reconciliation data needs to be generated. Example: `false`. |
| `LocationCountry` | string | No | The ISO 3166-1 alpha-3 country code for the associated location. Example: `USA`. |
| `LocationJurisdiction` | string | No | The jurisdiction or state code for the associated location. Example: `AL`. |
| `LocationCounty` | string | No | The county name for the associated location. Example: `Montgomery`. |
| `LocationCountyCode` | string | No | The county code for the associated location. Example: `MONT`. |
| `LocationCity` | string | No | The city name for the associated location. Example: `Montgomery`. |
| `LocationTerminalCode` | string | No | The terminal code associated with the location. Example: `T01ME1000`. |
| `LocationDescription` | string | No | A human-readable description of the associated location. Example: `Main Distribution Terminal`. |
| `LocationCustomIdCode` | string | No | A client-defined identifier for the associated location. Example: `CUST-001`. |
| `LocationAddressLine1` | string | No | The first line of the street address for the associated location. Example: `123 Main Street`. |
| `LocationAddressLine2` | string | No | The second line of the street address for the associated location. Example: `Suite 200`. |
| `LocationPostalCode` | string | No | The postal or ZIP code for the associated location. Example: `36104`. |
| `LocationAirportCode` | string | No | The airport code for the associated location, if applicable. Example: `MGM`. |
| `LocationAlternateJurisdiction` | string | No | An alternate jurisdiction designation for the associated location, when applicable. Example: `AL-ALT`. |
| `FiledBy` | string | No | The user who filed the return. Example: `jsmith`. |
| `PreparedBy` | string | No | The user who prepared the return. Example: `jsmith`. |
| `ReviewedBy` | string | No | The user who reviewed the return. Example: `jdoe`. |
| `ApprovedBy` | string | No | The user who approved the return. Example: `admin`. |
| `LastGeneratedDate` | string | No | The date the return was last generated. Example: `2024-01-15T09:30:00`. |
| `PostedDate` | string | No | The date the return was posted to GL or downstream systems. Example: `2024-01-20T14:22:00`. |
| `WorkflowTask` | string | No | The current workflow task code. Example: `REVIEW`. |
| `WorkflowTaskDescription` | string | No | The human-readable description of the current workflow task. Example: `Pending Review`. |
| `WorkflowName` | string | No | The assigned workflow name. Example: `Standard Filing Workflow`. |
| `TotalTax` | number | No | The total calculated tax amount for the return. Example: `184`. |
| `CollectionAllowance` | number | No | The collection allowance amount credited on the return. Example: `0`. |
| `TotalAmountDue` | number | No | The total amount due after taxes and allowances. Example: `184`. |
| `TaxpayerGroup` | string | No | The taxpayer group classification. Example: `Group A`. |
| `LicenseNumber` | string | No | The license or registration number. Example: `LIC-AL-2024-001`. |
| `SubmissionType` | string | No | The submission type indicator character. Example: `P`. |
| `SubmissionTypeDisplay` | string | No | The human-readable display name for the submission type. Example: `Paper`. |
| `ThresholdAmount` | number | No | The amount-due threshold for the return. Example: `0`. |
| `ReturnCalculationDate` | string | No | The date the return calculation was last performed. Example: `2024-01-15T09:30:00`. |
| `LastDataFileUploadDate` | string | No | The date of the last data file upload. Example: `2024-01-10T08:00:00`. |
| `LasteFileUploadDate` | string | No | The date of the last eFile upload. Example: `2024-01-12T10:15:00`. |
| `IncludeSchedules` | boolean | No | Whether schedules are included in the return. Example: `true`. |
| `CalculationViewInd` | string | No | The calculation view description. Example: `Current`. |
| `BackEndInd` | boolean | No | Whether this is a back-end session. Example: `false`. |
| `AmmendmentType` | string | No | The amendment type (ORIGINAL or AMENDED). Example: `ORIGINAL`. |
| `EFileHeaderId` | integer | No | The associated eFile header identifier, if an eFile has been created. Example: `6789`. |
| `CreatedBy` | string | No | The user who created the record. Example: `jsmith`. |
| `CreatedDate` | string | No | The date and time the record was created. Example: `2024-01-15T09:30:00`. |
| `UpdatedBy` | string | No | The user who last updated the record. Example: `jdoe`. |
| `UpdatedDate` | string | No | The date and time the record was last updated. Example: `2024-06-15T14:22:00`. |

## Example Request

```bash
curl -X POST "https://excise.avalara.com/api/v1/TaxSessions/Amend" \
  -H "Authorization: Basic <credentials>" \
  -H "Accept: application/json"
```