Suggestions:
System sets the reason code by default in the channel partner return in process screen. This code is populated as value ‘R01’. So it is very convenient for the users, they don’t have to enter the reason code manually.
In channel partner return, process screen, once the users open the process screen. Details such as site code, return option, apply tax and return option etc.
Channel Partner return menu exists in SCM –> Purchase-> Channel Partner return.