HMRC : How to change access code – two step verification

I have listed below 4 scenarios :

A. If you wish to change your telephone number or how you receive the code you can do this by logging into your business tax account and following these steps:

  1. Select the Manage account link which is shown on the top menu bar.
  2. Under the account details heading, select the view or change your account details link.
  3. Next to the Government Gateway details heading, select the Manage your Government Gateway details link.
  4. Click `Your Government Gateway profile`
  5. Select the How you get access codes link.
  6. Then change, add or delete the entries on that screen as required.

B. If you cannot log into your business tax account, but someone else in your business who is an administrator can, they can follow these steps:

  1. Select the Manage account link which is shown on the top menu bar.
  2. Select the Add or delete a team member link.
  3. Select the Manage link for the required team member.
  4. Select the Remove (name of user) security preferences link.

C. If no one can log into business tax account you can contact HMRC:

Via Webchat : Link ; then click Ask HMRC online

or

Via Telephone : Online Services Helpdesk: 0300 200 3600
Phone line opening hours are:
Monday to Friday: 8am to 6pm

D. If all else fails, contact us to file you tax return. We will just need your UTR. If you do not have a UTR we can apply it for you but this will take time.

Source:
Employer Bulletin June 2022