# Single-use exemptions

Source: https://developer.avalara.com/avatax-dm-combined-erp/sales-tax-badge/transactions/exemptions/exemption-single-use/

# Single-use exemptions

Use purchase order numbers in conjunction with customer codes to trigger a single use exemption. In this case, the purchase order number present on the transaction must also be stored within the customer's exemption record.

```
{	"lines": [	    {		"number": "1",		"quantity": 1,		"amount": 100,		"taxCode": "PC002386",		"itemCode": "CARPET",		"description": "Carpeting"	    }	],        "addresses": {		"singleLocation": {		"line1": "2000 Main Street",		"city": "Irvine",		"region": "CA",		"country": "US",		"postalCode": "92614"	    }	},	"type": "SalesInvoice",	"code": "InvoiceNumberHere",	"companyCode": "DEFAULT",	"date": "2021-02-28",	"customerCode": "ABC",	"purchaseOrderNo": "123456789",	"commit": true,	"currencyCode": "USD",	"description": "Carpeting and tools"}
```

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