How can I clear the previous tax return? I prepared tax return on TurboTax last year, but filed it in different way. I already cleared and start over, but it didn't work

[DawnC0]

If you are using the Online version of TurboTax, you can't make any changes to the 2017 return.   It will just stay like it is in your account, but you can ignore it as it has no effect on what you actually filed.   Each October when e-filing shuts down, those tax returns become un-editable in TurboTax Onlne.

Let's say you didn't file it 'in a different way' and needed to complete it.  In this case, you would need to download the 2017 desktop software, transfer the tax file from Online to your desktop software and complete it using that, but even if you did that, the Online version will remain unchanged.  

If you did a Clear and Start Over recently, it only affected your 2018 tax return, not 2017.