This endpoint will modify a pending award transaction . There will be no change in the status of the transaction. However, the value of the attributes may change. You are not allowed to change a transaction that has already been approved or rejected.
It is expected that the system calling the API knows what the id of the transaction is- which means they’d have to store the id at their end. This may be counter intuitive.
Note: You can get a Transaction ID through List all Transactions API. It is the unique ID that every transaction is associated with.