This is my response to you:
1. You will need to execute and register the "Deed of Rectification";
2. You will need to pay the stamp duty as well as the registration fees at the office of the Registrar;
3. An example of a Deed of Rectification herein is like: this:http://www.tnreginet.net/pdf/Public_Utility_Forms_full/Deed%20of%20Rectification.doc
4. Make the changes in the clauses and register the same.