CannotUpdateAccountTypeId
Example
{
	"code": "CannotUpdateAccountTypeId",
	"target": "Unknown",
	"details": [
		{
			"code": "CannotUpdateAccountTypeId",
			"number": 1713,
			"message": "Cannot update AccountTypeId from and to FirmClient.",
			"description": "AccountTypeId of FirmClient can only be created during the account creation and cannot be moved to or from that value.",
			"faultCode": "Client",
			"helpLink": "http://developer.avalara.com/avatax/errors/CannotUpdateAccountTypeId",
			"severity": "Error"
		}
	]
}
Explanation

For Firm Clients, the AccountTypeId can only be created during account creation. It is not possible to update this value after account creation.