Ideally you should go back to who did it and they should amend it for free if it was their error.
To amend a return you did somewhere else or you don't have the original .tax file, you would first have to fill out Turbo Tax like you are doing the original return and pay for it. You have to recreate the actual wrong original return. Then when it matches each line that you really filed you have to tell Turbo Tax you will mail it so it thinks it was filed. Then you can amend it.
You would have to buy the prior year Desktop program here. They only sell the last 3 years. You need a full Windows or Mac computer to install it on
https://turbotax.intuit.com/personal-taxes/past-years-products