you may not be able to get to the VM. You may have to reset the system and start over if the PW is not avaialble. I cannot find a way to reset only the VM password and retain the VM. You may want to contact NEC directly in case they have a way that isnt in the manual. The manual seem to indicate you need to reset the entire system. NEC DT300 Series User Manual To Change Security Password
You will probably need to add the extension name via system programming. The following installation manual for the NEC Professional Level ll phone system may help (copy & paste) http://pdf.textfiles.com/manuals/TELECOM-A-E/Electra%20Professional%20Level%20III%20Install%20Manual.pdf
