"C corp is the correct filing, we used S corp for 2015 - 2018."
You will have to purchase the prior years' TurboTax Business versions (2015-2017) to amend those returns.
See https://turbotax.intuit.com/personal-taxes/past-years-products/2015/
C corp is the correct filing, we used S corp for 2015 - 2018.
"C corp is the correct filing, we used S corp for 2015 - 2018."
You will have to purchase the prior years' TurboTax Business versions (2015-2017) to amend those returns.
See https://turbotax.intuit.com/personal-taxes/past-years-products/2015/
Yes I have them when I try to amend it won't allow me to edit the type of corp
Correct, you can't edit the type of corp. You need to correct the error by filing Form 1120 instead of 1120-S.
Since it's not Amendment how does that affect the prior filings?