Use the online service or postal form to apply to reduce your Self Assessment payments on account.
To reduce the amounts you’ve been asked to pay if:
- your business profits or other income goes down
- the tax relief you are entitled to goes up
- use the online service (sign-in or set up a Government Gateway account)
- fill in the postal form on-screen, print and post it to HM Revenue and Customs.
You must claim by 31 January after the end of the tax year - for example by 31 January 2017 for the year 2015 to 2016.
Related forms and guidance
When and why you have to make payments on account for Self Assessment.