Return Deliveries from Goods Receipt Blocked Stock 
Use
If you accepted the goods conditionally, i.e. by posting them to goods receipt blocked stock, you enter the return delivery with movement type 124 (return delivery from GR blocked stock) instead of movement type 122 (return delivery to vendor).
Activities
You can use either of the following two documents as a reference:
In this case, the items are assigned with movement type 124.
In this case, choose movement type 124.
Post the goods receipt as described in the section
Return Delivery.Results of the Return Delivery Posting
Since the goods in goods receipt blocked stock are not yet part of the company’s own stock and are not valuated, the return delivery simply reduces goods receipt blocked stock in the purchase order history.
The system creates a material document, which serves as proof of the return delivery.