Could I change the ring duration (before rolling over to voicemail or another person/extension) for a phone?

Yes. If the phone is assigned to a User Account, then that user can configure this by logging in at, clicking on Call Handling & Voicemail and then Advanced Options and then moving the slider under Ring Duration.

If this is a Room Phone, it can only be changed by an Office Admin. Login at, click on Admin Settings, then select Desk Phones, and then click Room Phones, click Options next to the phone and choose Edit.