Hi Dwarik,
This program Rebuild commitments for purchase requisitions and purchase orders
Don't worry at all while running RKANBU01, this program will recalculate/refresh commitment from PO/PR.
My suggestion is to run CJEN (refresh Project database) and CJBN (recalculate assigned values) also after running RKANBU01.
*rewards points if it is useful.
Regards
Gaurav Ahuja