I have 10 items that I put under the default vendor when I first set up my account and I have rung up many sales for the items with the vendor set as the default.
Now I want to change the vendor to "American Rag", when I pull up the sales history do I see the transaction that were rung up under the Default vendor?
Yes, the sales history of the item under both vendors will be displayed so you will see all sales and not just the sales after the change.
How do I change the vendor on an item: This can be done on CAS, master item screen by modifying your item. If you have many to modify you may want to consider importing the modifications using the item maintenance import.