Client moved on December from CO to UT. Can he be a part-year resident for both?

[Golfer2016]

Does he have to pick one state to be a resident?  He moved late in the year.  CO has a lower tax rate so I want him to have most income taxed in CO.  I was going to call him a PY resident in CO and then a PY resident in Utah.  Utah's definition of residency is domicile, but he was also in Utah much less than 180 days. 

Also, for his address will be Ok to put Utah since he abandoned his CO address?

[Just-Lisa-Now-]

part year - part year

[abctax55]

" CO has a lower tax rate so I want him to have most income taxed in CO. "

THAT is completely irrelevant.  The income is taxed by the state it was EARNED in; you don't get to pick the one with the lesser tax rate.

Part Year for each state.