change of service tax zone

dear sir           

We are involve in constructions services in many state so we have centralized registration in  Gujarat office and  it is also our permanent office  and all the services tax related compliance are settled from Gujarat office  now we want  it from Delhi office .for its what exactly we should do .whether we should file fresh application for registration  in CGO Delhi or submit  application in Gujarat ST office for address change. Pls help me