Is there any way to restrict the buyer not to reduce the PO quantity below intransit quantity?

I have following query, please advise, 

I have PO with 100 qty and Supplier has sent the ASN for 100 qty, After some days while quantity is intransit, Buyer has reduced the PO quantity from 100 to 50, so now my PO is for 50 qty and ASN is for 100 qty,

Now I have a problem in receiving the ASN as system allows the user to receive the ASN but it fails at the end after user scans all the LPN and Serials, as our over receipt tolerance is 0 with option as reject.

my requirement is if there any way to restrict the buyer not to reduce the PO quantity below intransit quantity?