We do not like to see you go. But if you must, here are the steps:

Please click on the blue "Contact US" button on this page or click on the following link: https://customercare.webmd.com/hc/en-us/requests/new?ticket_form_id=114094016951 and fill out the request form. Select 'WebMD Customer Care' from the 'choose your issue' drop down. For the feedback category please select 'profile and registration'. Fill out the rest of the form and please indicate that you would like to cancel your account. 

If you are a professional, looking to delete or add information to the Physician Directory, please see the following FAQ: Updating/Correcting Physician Directory Listing – WebMD Customer Care