You can cancel any of your pledges from the 'My Pledges' section of your Crowdfunder profile (up to 24 hours before a project closes). This also removes you from the project's backers list. 

If a project is on 'Instant Payments', the funds will leave you account at the time of pledging. Therefore, if you would like to cancel your pledge and request a refund, you will need to contact the project owner directly to do so.

Please note: If you have used Guest Checkout, you will need to follow the link in the 'thanks for your pledge' email, and signup as a full member to be able to manage your pledges.