I am unable to use all my foreign tax credit for year 2017. I will have left over approx $577. I know I can carry forward the unused amount, but, don't think I'll be able to use all it anytime soon given that I won't be able to use everything I'll get in 2018. I read that I can carry back the foreign tax to preceding year(s). I only used $62 in 2016 and $62 in 2015. How do I go about applying some of the unused foreign tax, approx $238, to 2016 and before? Would I have to execute an amended 2016 return?
