How to modify Overview variant in Transaction CA72?

Hello Everyone,

I am trying to use transaction CA72 (PRT Usage in PM Routings) for searching PRTs used on PM Task lists. The output of this report is not having the required information and would like to modify it. Overview variant on the input selection screen has only one option to choose from i.e. "L00000000240". Is there a configuration where I can create a new overview variant for this transaction? I tried searching but could find one.

Thanks in advance.

Vijay