Hello Chucksters,
Typically, the calendar is based on a particular login, so if you're want to change it, then you just use a different login and a different "default" calendar. When I was I looking this up, there were also a couple of forum links that went back here: Change default Google Calendar.
If you have any further questions, please contact technical support or leave a comment at the bottom of the page.
Regards,
Arnel C.