Using the “Re-dial” Command
1. Press and hold 
for two seconds.
2. After the tone, say “Re-dial.” Once connected, the person called will be heard through the audio speakers.
See also:
Automatic Operation
AUTO (Automatic): When automatic operation is active, the system controls the inside temperature, the air delivery, and the fan speed.
Use the steps below to place the entire system in automatic mode ...
Tire Pressure Monitor
This vehicle may have a Tire Pressure Monitor System (TPMS).
The TPMS warning light alerts you to a significant loss in pressure of one of
the vehicle's tires. If the warning light comes on, ...
Warranty
OnStar equipment may be warranted as part of the new-vehicle limited warranty. The manufacturer of the vehicle furnishes detailed warranty information. ...