This is tricky to answer since every 3PL / WMS have their own processes, which may or may not allow for order edits to be possible.
Some make it possible to edit everything in the order
Some allow to change only certain aspects of the order
Some don't allow for any changes, except for order cancellations.
If you want us to check whether we can integrate with your 3PL / WMS provider, drop us a message!