Mass Update Default Buyer on Item Master

We had one of our buyers leave recently.  On our item master, we have the buyer assigned on the Purchasing tab > Default Buyer.  When we have requisitions auto-created, they error out during the Requisition Import process, where for the moment we are re-setting the error field, and assigning the buyer id in the table, and re-running the Requisition Import.  Right now, we're trying to work on updating in a mass process the default buyer on our items assigned to our end-dated buyer.
How are you handling things like this when your buyers leave the business?  Are you assigning buyers on the item master, then having to update them to a new buyer value?  Is there a built-in process to handle this?