Identify USERS attached to Custom Programs

I am working on END_DATE users but I received the below note from a member of our Functional Team.

Does someone have a script that can find Users whose account is tied to a custom program?

I would appreciate any advice you may have on how I can identify and detach users from a custom program.

NOTE FROM FUNTIONAL TEAM MEMBER:

"Please do not end date any users in Oracle.  There are some custom programs which require the users to be active or processes will fail, including the buyer requisition imports. The process here for secuirty reasons has been to end date the at the responsibility/role level versus at the user level.  This process was established due to items and/or PO's being assigned to obsolete buyers, If you end date a lot of these accounts, some errors  will occur in the APP, specifically some customizations. I have attached a copy of how some of the end dates have been performed at