Hi folks, first post in this forum. I've been using LRTimelapse for a while and finally bought a crossgrade license from private to pro yesterday. The instructions to activate the new crossgrade license key state to go to the "Licensing" menu in LRTimelapse and click "Activate License Key," however, this option is grayed out and cannot be selected for me. It seems I need to deactivate my private license key before I activate my crossgrade license key. I just want to confirm - is this the correct way to activate this license? I wanted to ask in the event that I deactivate my private license key, cannot activate the new key, and am left with only the free version.

Yes, you need to deactivate your private license first, then activate the Pro license.
In any case, you can always activate and deactivate any license as you need it.