In EDI 855-Can supplier make line level quantity change, if yes, how to stop the quantity update?

Summary:

We have an issue where is supplier has initiated quantity update at the line level and the 855 is process successfully and Change order has made qty changes on the PO.
Quantity change at line level was never an intended solution for the customer. We would like to know is it possible to restrict qty change at line level from 855?

Code Snippet (add any code snippets that support your topic, if applicable):

Code we received in 855 for Qty change