Virtual Receptionist allows all calls to be answered automatically - 24/7/365. Set up a customizable greetings that can route your callers to specific departments or extensions, and you can even give your Virtual Receptionist its own office hours with time-of-day scheduling, ensuring your customers hear the right greeting at the right time. Combine with other advanced features like rollover hunting and call queue with hold music that makes the wait enjoyable to ensure you never miss a call again.
This is it. If you are not satisfied with the custom voicemail greeting, then follow the same steps and do it again.

For many of us, our professional voicemail greeting is a crucial first impression. For others, it might be something that our clients and partners hear over and over again. An unprofessional voicemail greeting reflects poorly on you, and while it’s easy to overlook, it’s just as easy to fix. Script it out beforehand. Make sure information is specific and up-to-date. Keep it short. Use a quality recording. Smile when you speak. Script your voicemail message
From the Skype for Business desktop app (if you are running Click-2-Run build C2R 8201.1002 or later), select Set Up Voice Mail. Change your Call Answering Rules You can change what options your callers have when they reach the voicemail service; get disconnected, hear your greeting, record a message, choose to be transferred to the number or user you select. Change your prompt language This is the prompt language that is played to callers. For list of supported languages, see Languages for voicemail greetings and messages from Skype for Business. Configure your Out of Office greeting This is the customized greeting message that is played to callers when your status is Out of Office. This option can be activated "Always," when you have an active "Auto Reply" in Outlook, or whenever you have an out-of-office calendar appointment.  Where you can get your voicemail messages from