Log in at trala.com using the email associated with your account.

On the left sidebar, click on the 'Account and Subscription' icon. Then select Manage Subscriptions.

This will bring you to new a window. Click the button that says Edit Plan.

From there, select your teacher, which subscription plan you would like change to, and hit Continue.

You'll be prompted to schedule the first lesson with this new subscription, and your recurring schedule will automatically update according to your new plan!