Use form MLR RCT1 to report changes to your business, if you registered with HM Revenue and Customs (HMRC) by post.
Ref: MLR RCT1
You should only complete and send form MLR RCT1 if all of the following apply:
If you have registered or renewed using the online service, you can sign in and make any necessary changes online. Do not send form MLR RCT1.
If you are using an older browser, like Internet Explorer 8, you’ll need to update it or use a different browser. Find out more about browsers.
You’ll need to fill in the form fully before you can print it. You can’t save a partly completed form so we suggest you gather all your information together before you begin to fill it in.
Don’t include personal or financial information like your National Insurance number or credit card details.