How the boot image can detect the GUID of the computer and ask to delete it from SCCM if already there?

Hi,

I need to deploy Win7 to computer already in SCCM 2012 R2.

Actually, the deployment team need to manually delete the record of the computer in SCCM to be able to see task sequence.

I want to add a pre-stage command who will run a script. This script must ask for the future computer name and delete the GUID and computer associate with in SCCM.

Can someone help?