Make sure the relevant safety warnings have been read and understood before operating the phone features. See PHONE SAFETY.
If two calls are in progress on the same phone, both calls can be merged into one conference call. Select the displayed Merge option.
While the calls are merged, touch the hold icon or the mute icon to mute both calls. Alternatively, touch the end call icon to end both calls.
Merge cannot be deselected. If one caller ends the call, the remaining call stays active. See PHONE SYSTEM ICONS.