In Pocket PA there is not an option to EDIT a payment
The process is that the payment will need to be deleted first and then added in again as a new payment.
Start on the Income Screen via the Financials menu dropdown.
On the Income Screen at the bottom, there will be a list of all payments you've created under 4 different tabs.
You can click on each one by selecting the green date of the payment that you wish to see the payment details for.
Click on the Red Delete Payment button to delete.
Confirm on the pop-up that you definitely want to Delete the Payment or press Cancel