Hello Suchita,
Unfortunately a modification performed within the "Parameters" tab of a user do not generate changedocs, so SUIM will not show this modification.
I'd encourage you to perform tests activating the Security Audit Log report (SM19) to see if such change generates a thread there (analyze it through SM20). I'm afraid however that this will not be that specific... I think it'll only show something like "User Master Record Changed".
Hopefully this information will be useful.
Regards,
Felipe Fonseca