Employee Turnover

We are new to RingCentral and was looking for some best practice guidance. On the sales side of our organization there is quite a bit of employee turnover. There are times when a licensed extension could be unused for weeks. Since the employees' DID's are provided to customers, when an employee leaves we do not want the calls to go unattended. I have implemented some work arounds but they seem a bit time consuming. Any ideas would be appreciated.

Thank you