From Page 39 of the manual:
(right softkey) during a call displays a list of
features you may use during the course of a call. To select an
option, press the corresponding keypad number or highlight
the option and press . The following options are available
through the Options menu:
(1) Key Mute/Unmute
allows you to mute the microphone
on your phone so the caller is unable to hear any sound.
(2) Turn Speaker On
enables the speakerphone feature.
(3) Set Whisper
increases the microphone to its maximum
level. During a call turn on Set Whisper when speaking
softly or when the caller cannot hear your voice clearly.
This mode is useful in meetings or public places.
(4) Call History
checks your call log for Outgoing, Incoming,
Missed, and Recent calls. You can also erase the logs from
accesses the Contacts menu.
(6) 3-Way Call
allows you to talk to two different people at
the same time. (For more information, see “Making a
Three-Way Call” on page 189.)
accesses the Messaging menu options.
(8) Voice Memo
allows you to record incoming audio from
your conversation. (For more information, see “Managing
Voice Memos” on page 135.)
accesses the Tools menu options.