Anyway to blank out the source location id on Ready-To-Ship Screen?

Summary

The Source Location field is always populated on the Ready-To-Ship screen - but that's a field we want our supplier to enter.

Content

We're in the process of converting our freight terms to collect for all our inbound POs and we are using the Ready-To-Ship screen to capture information from our suppliers regarding what's ready for pickup  - quantity, count, dates etc.  One of the key pieces of information that the supplier needs to provide is the actual pickup location.  In OTM, the pickup location needs to be populated on the order base line and what we're discovering is that a lot of our suppliers are not updating the field with the actual source location since it's already filled in with a value.