Changing your subdomain is a simple task that can be done at any time.
From Settings > Venue profile choose the Basics option.
On the page you will see a 'Change Subdomain' section, from here just enter the new subdomain you want to change to and choose 'Change subdomain and reload page'. The change will occur instantaneously and your previous subdomain will redirect to your new one.
Note: We currently don't support the ability to use your own domain (e.g. mydomain.com) for your Skedda account. This is primarily for security reasons (i.e. the requirement for a valid SSL certificate for secure HTTPS communication).