When your business is closed for vacation or holidays, it’s imperative that you set appropriate expectations for a callback and to provide an alternative coverage option, if available. The following greeting accomplishes this succinctly.
Rollover Hunting is a feature that is managed by the Account Manager or Phone Manager. It allows incoming calls to your primary phone line to roll over to the next available line and, if al l lines are busy or not answered, the call can roll over to voicemail. It will hunt through all lines in the group once to find an idle line. You can configure multiple hunt groups and the number of rings before the call is routed to the next li ne. Each hunt group must have a minimum of two lines and a unique primary number. There are three hunt sequence options:

I have a confession to make: I haven’t recorded a new voicemail greeting since 2014. In the past four years, I (hopefully) have become more articulate, poised, and self-assured. But hear my voicemail recording, and you’d think I was still new to the work world, a little unsure of myself — and probably not an authority. Obviously I need toupdate it. And if you haven’t changed your voicemail greeting in over a year, you’re likely in the same boat. After all, a professional voicemail recording boosts your credibility, makes you seem more competent, and encourages whoever’s listening to it to continue the relationship. A relatively unprofessional one — like mine, for instance — does the opposite: It encourages prospects, recruiters, and potential connections to run in the other direction. With that in mind, I’ve written 18 unique voicemail greetings for every situation. Pick your favorite, practice a few times, then record your new voicemail.
https://smith.ai/blog/28-business-voicemail-greetings-for-main-office-and-personal-numbers-formal-informal-modern-and-just-hilarious