Many companies choose to implement vendor payment journal approval workflow. The key difference between this and other workflows is that instead of involving approval before posting, it is designed to require approval before generating the payment file. Once the workflow is approved, the 'Generate payment' button becomes active and the journal is no longer editable. The user then generates the file to send to the bank. This all works well for all payment types, except foreign currency transfers.
The problem with forex transfers is that the bank usually provides the spot rate after the file is sent, meaning that the user then needs to edit the payment journal to enter the rate and then submit for approval again.
It would be good if we could provide the option to enter the rate for an approved journal, without letting them edit anything else, and without having to submit to approval again.