"We already have a website and just want Communico's Attend and Reserve pages to use our domain, can we do this?"
Yes, but only with subdomains. If you create a subdomain your events can be displayed with a url like this events.ourcurrentdomain.org/events
And you could do the same for room reservation pages using Reserve too.
You would just need to supply Communico with the subdomains you have created and the modules to use them for. Typically events and rooms are used for Attend and Reserve but the sub domains can be anything you choose.
You could also set up a secondary domain www.seasonslibraryevents.org and use this for events pages.
Important: As the Attend and Reserve pages are hosted by Communico we can't use your domain to display in this format ourcurrentdomain.org/events