HELP ME WITH THIS SPEC VERY URGENT

Program: For a set of selected material Read MARA-prdha and update mvke-prodh and write out a success/fail report. All error materials downloaded to a file.

Selection Screen:

Material (mvke-matnr)

Sales Org (mvke-vkorg)

Dis.Cha (mvke-vtweg)

I NEED TO KNOW WHAT FUNCTION MODULE USED IN BAPI .

SEND ME SOME SAMPLE PROGRAM.