To clarify, you file part-year resident returns only if you literally moved from one state to the other during the tax year.
However, if your situation is that you own homes in two states and spend time in both, then state law will determine which is your State of Residence for state income tax purposes. As @Bsch4477 said, you can't just pick and choose.
Bottom line: we need more details about your situation in order to answer your question correctly. What are the two states? How much time did you spend in each during the year? In what state is your drivers license, vehicle registration, voter registration? In which state do you work?
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
