Yes, you can. You may need to update your self-assessment tax return for various reasons. For example, if you have made mistakes.
To make changes to your tax return, you need to complete and submit a new tax return with updated information. You can either do it online or by post, explaining the reasons for updates in the attachment. Let’s look at it step by step:
You download and print out official tax return forms.
You fill in the forms and note down “amendment” on the pages which you have updated. Note that you must include your full name and UTR in your self-assessment tax return.
You send the updated version to HMRC.
Based on your updated self-assessment tax return, your tax burden will be reassessed. You will have to either pay additional taxes or claim a rebate.
You can update tax returns for the last two tax years without notifying HMRC. However, if you need to make changes to older tax returns, you must notify HMRC first. You must provide details of:
what tax return you need to update
why you paid too much or too little tax
how much you need to pay or get refunded.