Credit Order- "Return Reason'' while entering credit order

Hi,

Is there any way to make mandatory ''Return Reason'' while entering credit order?

We are paying to third party for returns based on their nature of return, some times the users are leaving this field empty and we cannot able to trace it out the reasons of return.

could you please let us know  the way to make this entry as mandatory.

Waiting for your response !

Regards,

Tushar