In my opinion your question is not clear
e.g you did not mentioned whether shipment is inbound shipment or outbound shipment as far as shipment are concern you create a shipment and assign outbound or inbound delivery to that.
from a process flow perspective
if it is a Outbound shipment then you assign outbound delivery to that and Outbound delivery gets created from Sales Order or Stock Transport Order which is already having the customer number so you cannot make change in shipment similarly if inbound then you create Inbound delivery against Purchase order which you attach with inbound shipment and if the predecessor document are having different vendor then again you cannot change the vendor in delivery via the shipment route
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.