As an Office Manager, you can change each user's voicemail greeting and settings, including day/night and holiday greetings.
To add a greeting, click the "Add Greeting" button. You will have the following options:
Text-To-Speech: This allows you to type out a message, which will then be recorded by a computer-generated voice.
Upload: This option allows you to upload a media file from your computer.
Record: This option will call your desk phone, and prompt you to record a new voicemail greeting. (Greeting name is required before the system will call you)
Once you have recorded a new greeting, you can select it from the drop down list to make it your primary voicemail greeting.