problem in updating nast table

Hi all,

In my program if certain condition is failed i need to change the transmission medium from 5 to 1 and update in nast table but the problem is if nacha is 1 am using rv_message_update_single function module to update to nast in my custom program it is changing nacha to 1 once it comes to end it is calling RSNAST00 program from there again it is taking the old values and updating in the nast table how to resolve the isssue.

IN RSNAST00 perform (tnapr-ronam) in program (tnapr-pgnam) using returncode
                                                          us_screen
                                                          if found.
* restore original NAST record (in case TNAPR-RONAM changed something)
     nast = temp_nast. here temp_nast contains the old value

in my custom program
FORM entry USING return_code us_screen. is used here am changing the nacha but again it is calling the RSNAST00 and updating the old value how to resolve the issue.

Regards,

Karthik