Try online, or email the request.Is the change delivery request on the UPS app and site giving anyone else errors or happened in the past for you? I'm trying to change the delivery of the iPhone to pickup at an access point for tomorrow but it keeps giving me errors. The site says technical issues and the app pops up an error of "a system that is necessary to fulfill your request is currently unavailable.."
Here is the link to email UPS for U.S. customers, request hold at CC, access point here. Sign-in when sending the email. They will respond within a couple of hours.
https://www.ups.com/upsemail/input?loc=en_US