I accidently filed my federal tax return in 2015 uing 1040-EZ while I was a non-resident alien. Now I was planning to file my tax return as non-resident alient (1040-NR through sprintax) for 2017 as I am still a non-alien resident (based on IRS rules). Do I need to correct my 2015 tax return as well? And if yes, how to do that? Please help ... View more