Is there a way to change the calendar so that the only dates that are open or May 15 through September 15. Thus, if there are four partners they can book 25% of the time from May 15 through September 15.

Yes, we have a similar challenge. I have reached out to customer support because we have unlimited usage in winter and limited in summer.

Is there a way to change the calendar so that the only dates that are open or May 15 through September 15. Thus, if there are four partners they can book 25% of the time from May 15 through September 15.

The only way to do that would be to administratively book all the other slots - which obviously isn't a great solution but would be doable with a bit of work. We don't really have an "active" season setting. The other thing you could do is to go in and reduce everyone's percentages to zero at the end of the season and than change it back at the beginning of the next. Also, not terribly satisfying, but that might get you over the hump until we have a chance to think this one through.