You change ISO certification body by asking a new accredited body to recognize the certificate you hold and to issue its own, while the current certificate stays valid. The registrar can change. The management system, the standard, and the scope you already certified stay with you.
What do you do first?
Confirm the certificate is still in date and is still active. Collect the certificate and the latest audit reports. Send the application and choose Transfer from another body. Name the standard, paste the scope, and include the expiry date in the scope notes. IAF Consultancy replies with a written offer that states the scope, the timing, and the price. That offer shows whether the move stays a transfer, or whether the file has to be audited as a new certification.
What happens after you accept the offer?
You authorize a request for the audit file, and you send the copies you already hold so the review can start. IAF Consultancy reviews the certification. A visit is added only when the documents leave a question that the paper cannot answer. The checks are listed in what a pre-transfer review checks.
SMG, accredited by IAS under MSCB-153, makes the certification decision and issues the certificate when the review supports it. IAF Consultancy audits. The certificate customers file is the one SMG issues.
What do you tell the body you are leaving?
Tell them you are transferring, and leave the current certificate in force until the new one is issued. Withdrawing it first is how a company reaches a customer with nothing to send. The wording and the order are in when to tell your certification body. Why the dates have to overlap is in avoiding a gap.
What should the new certificate show?
It should name the same standard and the scope already certified, carry the expiry date you already have, and show an accreditation mark a customer can check. SMG's accreditation number is MSCB-153. If you want sites or activities added at the same time, that part is quoted as an extension. See changing scope during a transfer.
The rules behind the move are in how to transfer an ISO certificate. The reasons companies make the change are in why companies change.