You can do it physically going to the branch u have registered or through online. Fill up one page of form and a draft of rs 500 will be required. Your registration number and Ur course old /new will remain the same.
i sent the phycially but they return me with remarks tha plZ REFER UR APPLICATION ALONG WITH DD ACTLLY I SENT DD ALONG WITH REVALIDATION FORM NT WITH APPLICATION SO SHLD I SENT APPLICATION AND WHT SHLD I WRITE IN APPLICATION I MEAN FORMAT