Hey it is possible to delete the link PO/IR ? Reset value in the created from on IR?

No, when you create a new transaction via transform (e.g. create a IR from a PO), the only way to get rid of that link is to delete the created transaction (e.g. IR)

Yes but my problèm is the IR is post on closed period I'm looking for a way to void the IR without deleting and therefore be able to receive from the PO again