PO Acknowledgment error

Hi Experts,

We are using EDI system to send the PO to vendor system and create sales order and after creation Acknowledgment will post to our PO.

here in some cases Ack idoc is failing with error 'Acknowledgment for PO item xxxxxxxx xxxx contains quantity variance.

this error is due to quantity difference between po and sales order.

can you please help me to allow posting of ack idoc even there is a qunatity difference.

Thanks & Regards

Gopi