bapi to replace existing position ID

Hi

Can i have a bapi which replaces the existing Position ID with the recent position in HR Module.

If an employee changed from one designation to another designation in the same organisation then his position id will also be changes so generally we will goto some tcodes related to this change of position id and we will try to make modifications. But i want a bapi or any FM with which we can directly update or insert or replace the existing ID with the new one

Regards

Krishna