Yes!

If you're on a month-to-month plan you can switch to annual anytime from your Billing-->Manage Subscription tab. Just click the "Switch to Annual Plan" button:

If you're on an annual plan and would like to switch to month-to-month for your next billing cycle, simply submit a request to contact@mobile-text-alerts.com and a support rep will get that processed for you.

Note: Accounts in a current annual subscription cannot move to monthly billing until the next renewal date.