The following Webservice code can be used to Update Receipt Method on the AR Invoice. Some of the conditions that are required are that the Invoice need to be in Complete Status. The Complete button should be in enabled status. That is, if a receipt is applied on the invoice, then we cannot modify the Receipt Method on the Invoice.

Get the Customer Transaction ID for the Invoice using the following query:

select customer_trx_id from ra_customer_trx_all where trx_number = <ar_invoice_number>; 

WSDL used is: https://xxx-your-oracleserver.oraclecloud.com/fscmService/StandardReceiptService?WSDL

Code to update the Receipt Method is:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:typ="http://xmlns.oracle.com/apps/financials/receivables/transactions/invoices/invoiceService/types/" xmlns:inv="http://xmlns.oracle.com/apps/financials/receivables/transactions/invoices/invoiceService/" xmlns:typ1="http://xmlns.oracle.com/adf/svc/types/">
<soapenv:Header/>
<soapenv:Body>
   <typ:processUpdateCCToken>
      <typ:changeOperation>Create</typ:changeOperation>
      <!--Zero or more repetitions:-->
      <typ:updateCCToken>
      <inv:CustomerTrxId>9999938381</inv:CustomerTrxId>
      <inv:ReceiptMethod>New Receipt Method Name</inv:ReceiptMethod>
   </typ:updateCCToken>
      <typ:processControl>
         <typ1:partialFailureAllowed>true</typ1:partialFailureAllowed>
      </typ:processControl>
   </typ:processUpdateCCToken>
</soapenv:Body>
</soapenv:Envelope>