Upgrading webinar license dynamically based on number of registrants

[r-c-m]

Hello, I am hosting a webinar (requiring webinar license), and we are uncertain of the number of registrants/attendees. It might be greater than 500 people, but it could also be greater than 1,000 people. Is it possible to send the webinar registration/invitation and then upgrade the license later as needed? To do that, would I have to send a new invitation/link (I'd want to avoid that)? Thank you!