How do you change authority on save file?
Save file authorities can be changed using the standard authority commands (EDTOBJAUT, RVKOBJAUT, GRTOBJAUT, etc.) and specifying the type as a file. If you are referring to the fact the ownership or authority of an object changes when it is restored, the following quote from the OS/400 backup and recovery guide may offer some assistance.
"When you restore an object, the system determines what profile owns the restored object by using the following rules:
Ownership is restored to that profile if the profile that owns the object is on the system.
If the owner profile does not exist on the system, ownership of the object is given to the QDFTOWN (default owner) user profile.
If the object exists on the system and the owner on the system is different from the owner on the save media, the object is not restored unless ALWOBJDIF(*ALL) is specified. In that case, the object is restored and the owner on the system is used. "