Gravity Forms hook function code required. Gravity forms API Knowledge needed

1) When the user role changes - for example from Admin to Editor - we have custom roles setup. When this action happens in WordPress fire the second function. This happens by a user making a payment in this case. 2) Update that specific user entry in Gravity Forms. For that, you'll need a custom code where you can specify the form ID, field ID and entry ID you want to update. The user is logged in when they do this. This is an urgent project. Thanks