I think I filed a State return when I didn't need to. How do I amend my State return?

Amend it to what exactly?  Which state?

I reported income to Indiana that apparently wasn't earned there.  My wife got a new job this year, the job is based in Indiana, but she's only ever worked remotely.  She's never actually worked in the State of Indiana.  So I need to amend our Indiana return to zero.