I want to know the slip number for UPS → Yamato transfer
Change in delivery route after transfer to Yamato Transport
If you wish to change the delivery date after customs clearance, you will need the Yamato Transport slip number. However, only UPS, which has handed it over to Yamato Transport, knows that slip number. Unfortunately, UPS does not automatically tell the number to customers.
So, the easiest way to find out is to call UPS customer support .
If you tell them "I would like the Yamato Transport waybill number" along with the tracking number, they will tell you on the spot without having to wait.
If it is outside of customer support business hours or the phone lines are busy, you can contact customer support by email. The specific steps are described in the article "UPS → Yamato Transfer (mainly within Tokyo)".
*We don't know when UPS Japan will expand its delivery services outside of Tokyo, so some customers have applied for the change in method to the same as in Tokyo. That may be one option.