You can answer a call while you have another call in progress. To activate call waiting (network service), select Menu > Ctrl. panel > Settings and Phone > Call > Call waiting.
To answer the waiting call, press the call key. The first call is put on hold.
To switch between the two calls, select Swap.
To connect an incoming call or a call on hold with an active call and to disconnect yourself from the calls, select Options > Transfer.
To end the active call, press the end key.
To end both calls, select Options > End all calls.