Primary residence to rental - mortgage advice

[Sundar Velayutham]

Hi all, I need some advice on the kind of mortgage that is best for my primary home now that will become a rental in 6 months. I currently have a 15 year mortgage at 1.875%. I plan to keep this property and not sell for the next 10 years unless I am forced to financially. 
I can afford to pay the mortgage on it if the rental income falls short. 
Since rates are low I have to option to convert this loan to a 30year or an arm and lower my monthly payment. I can have cash flow and more interest paid to deduct in my taxes. I am not sure if I should refi now or just keep the 15 year mortgage. Please any advice is appreciated.