How to find out the user exit is implemented

Hi All,

Kindly let me know the process to be followed to find out the User exit is implemented in SAP system.

I have seen many senriors suggestions for some treads to check if there is any Exit is implemented in the process when the system is behaving differently rather standard.

Is it the only way with help of ABAP'er we can find out or the functional consultant also can find out through some procedure?

I tied in google for this doubt, but i could not get the relavant answer.Pleaea execuse me if this already answered.

Thanks,