How to Flush Out Inventory after migration

Hi Gurus,

I badly need your help. We are going to do migration from SAP to other system for certain production line and one of the task is to "flush out" the inventory quantity  from SAP after migration done. Please advise which transaction code I have to do and what is the movement type and the steps. Great if I can know the BAPI program to do so as well. Thank you so much in advance for your reply.

Thanks,

Kenzo