Setting Ring Volume
To change the ringer volume, use the + and - (plus and minus) buttons on your phone. Press repeatedly to change to different volume levels (1 through 14).
To mute the ringer, press the - (minus) button repeatedly until the mute symbol appears at the top of the screen.
Mute the Ringer Temporarily (for One Incoming Call)
During an incoming call, press the Silence soft key.
This will silence (mute) the ringer for this call only. The inbound call will still be "ringing" to your phone, giving you the option to answer, forward, reject, or ignore it.