If you have a single license key, but need to use it in more than one place (i.e. a host machine and a VPN):

You need to close out of all Microsoft Office applications before connecting or disconnecting from your VPN. Windward will see them as different machines when they’re connected vs. disconnected.

Quitting all Office applications will tell Windward that the Designer is no longer in use on that machine, and can be used on another.