From your Settings click 'Your Terms & Conditions':

As a Pro member you'll see the button 'add alternative t&cs'. Click this button

Name the new Terms and Conditions, add your body and statement and click save:

To change a bride's terms and conditions click the T&Cs tab from the menu:

Choose your alternative terms and conditions from the dropdown.

To revert back to your original terms and conditions click the refresh icon circled below

The new terms and conditions will show on your brides quote:

Please note that terms and conditions cannot be changed once they have been signed by a bride.