You can use the Status menu to switch off 'do not disturb.'
1.Press the Status soft key.
•To access the Status menu during a call, press the PHONE key and then press the Status soft key if shown.
2.If necessary use the up and down cursor keys to highlight Do Not Disturb.
•To clear the 'do not disturb' setting, press the Off soft key.
Access Control
Your system administrator can configure whether you can access this menu option. See Menu Access Control.