Amend the previous self assessment form

I had a call with HMRC today to clarify the wrong calculation of a previous period of tax. The adviser told me that I need to amend the previous form for 2021-2022 in order to pay back the incorrect repayment to HMRC. However, I can't find any button to amend the form. How can I amend it if there is no button for me to click?

Hi,

After logging into your personal tax account, click the Self Assessment tile on your account home page. Then click ‘ More details about your Self Assessment returns and payments’. Finally, selecting ‘Amend Self Assessment tax return for the tax year 2021 to 2022’ should allow you to amend your return.

If you cannot see this option, you may not be able to amend your return online. To allow us to update your return please write to us confirming the tax return you need to amend, and details of the change needed:

Self Assessment,
HMRC,
BX19 1AS 

Thank you.