To change your night greeting on a Samsung OfficeServ 100, 500, 7100, 7200 and 7400 phone system:

Press the voicemail button
Press * # 0000
Enter the system password
Press 1 to edit system prompts
Enter 1002 for the Night prompt
Press 1 to listen to the current prompt.  If this is not the prompt you want to record press * [...]

If you are using the Intramail with your NEC DSX telephone system (22B display tel phone) then your general delivery mailbox is usually set up as mailbox 600 (verify with your system administrator). This is the mailbox that callers are usually sent to if they press 0 or make no choice from the auto attendant [...]