A request to add an additional gratuity to a existing tender transaction.
| object (AccountInfo)  Information related to a given tender user. | |
| additionalGratuity | number <double>  A gratuity the user wishes to add to the tender payment. This is on top of any gratuity already applied. The tender provider should add a new payment or update an existing payment to handle the additional gratuity amount, if possible. | 
| object (CheckInfo)  Information about a check associated with a transaction | |
| transactionToUpdate | string <guid>  The identifier of an earlier tender transaction. This 
identifier is provided in the  | 
{- "accountInfo": {- "tenderIdentifier": "string",
- "properties": {- "key": "string",
- "value": "string",
- "tenderPropertyType": "FOLIO",
- "maxLength": "string"
 }
 },
- "transactionToUpdate": "string",
- "additionalGratuity": 0,
- "checkInfo": {- "guid": "string",
- "displayNumber": "string"
 }
}