If you wish to cancel any of the services you have with Purple Serve, simply log into the Client Area, go to "My Services" and select the service you wish to cancel. At the bottom of the page for the selected service click the "Request Cancellation" button.
If you have a domain name which you registered or transferred to Purple Serve, go to "My Domains" and select the domain you wish to administer. You then have the option of either transferring the domain to a different registrar or changing the Nameserver addresses to point it at a new web hosting provider.