My trip and expenses - change travel request link to standard application config

Hi Expert.

in our portal-> tab "My Trips and
Expenses". if we click "Change Travel Request" link in the
detail table, it leads to a custom application configuration. We are trying to
change it back to standatrd application configuration but I cannot find where
the link is and how to reassing the standard application config back to this iview.

Please advise. Really appreciate your help!