Savings Interest and Tax Code changes

I've had a couple of tax code changes over the last few months in order to pay back interest on savings from previous tax years. I'd like to know if I can just pay back the amount I owe as a lump sum and have my tax code changed back to normal so my monthly wage gets back to normal?

Hi Craig_AH,
Yes you can.
You can do this via your personal tax account.
Personal tax account: sign in or set up
Thank you. 

I have exactly the same problem, however I did log in to my personal account and pay the lump sum owing (apparently a 'simple payment') in January, but my tax code has been changed twice,regardless and I am now on a K code. When I log in to my personal account it has in red writing the threat that if I don't pay the tax "owing" by 19th June, it will incur charges and interest. Nothing the people at HMRC tell me (when I eventually get through) makes any sense at all.