do you have the program installed on the computer and have updated it prior to about 10/15/2020? you would also need the .tax2016 file. then you could open the program and click on the amend icon
it not, TT no longer supports 2016 so you would have to buy a copy from a website. that would likely be a beta version based on 2015. updates are no longer available so it may not produce an accurate starting return for 2016 nor a correct amended return.
why do you need to amend?