We will look at one of the Ellucian's delivered subroutine, S.CHECK.IF.WITHDRAWN, for this example. When checking for references in Colleague Studio, the list looks like this:
The above screen shows the usage of ESEARCH. You specify the folder/category of processes you want to search for. The above searches for UI/Webadvisor forms in ST. After the search, the result is saved in a savedlist named DTP. When you open DTP up, either in the terminal or in UI using SLED, you will see the more complete list of UI/Webadvisor forms that reference S.CHECK.IF.WITHDRAWN in ST.
Looking at the result, we can see more processes that reference S.CHECK.IF.WITHDRAWN than what Colleague Studio provides. I have found that Colleague doesn't not maintain references to custom processes very well, so ESEARCH is a good way to double-check. You can search for processes in corresponding applications:
appl.SUBROUTINES -> appl subroutines
appl.SOUCE -> appl screens
All of this requires you to have access to the terminal, of course. You can do a similar search using the window explorer on the Colleague file server, but that takes way longer for me.