Transferring Service
Push 
to request account transfer eligibility information. The Advisor can assist in canceling or removing account information. If OnStar receives information that vehicle ownership has changed, OnStar may send a voice message to the vehicle, requesting updated account information.
See also:
Roadside Assistance Program
U.S.: 1-888-881-3302
TTY Users (U.S.): 1-888-889-2438
Canada: 1-800-268-6800
Mexico: 01-800-466-0801
As the owner of a new GMC, you are automatically enrolled in the Roadside Assistance program.
...
Using the “Dial” or “Call” Command
1. Press and hold for two seconds.
2. Say “Dial” or “Call.” 3. Say the entire number without pausing, or say the name tag.
Once connected, the person called will be heard through the audio ...
Headphones
A. Battery cover
B. Channel 1 or 2 switch
C. Power button
D. Volume control
E. Power indicator light
The RSE includes two 2-channel wireless headphones that are dedicated to this system. Channe ...