Order Merge: combine two orders into one

Order Merge combines two orders from the same customer into one. Search finds the order number you type and says so plainly if Shopify cannot be reached. Before anything changes, Tacey refuses orders it cannot safely combine, such as an unpaid order, one with a return in progress or one with a subscription item, and when the two orders ship to different addresses you confirm which one is used; if either order changes before you click Confirm, Tacey asks again. If a merge is interrupted, it is recorded, can never add the same items twice, and can be finished with a retry. Merge history shows the real order numbers, what happened to each order in plain words, sorting, a date filter and a link to each order in Shopify. You get an email when a merge completes, the customer is told their orders were combined, and the combined items cannot be removed by the customer for a refund.