Ideas on a strategy to covert primary residence to rental then buy a new primary

[Jeff Eisman]

I need some help figure out the best way to do this while not taking the Tax hit and losing the equity we al ready have. 

What we own currently:

Rental property in CO with only a HELOC with a minimal balance. Capital gains if sold +- 300K

Primary residence in Charlotte NC low monthly payment capital gains if sold +- 250K

We would like to convert the primary residence to a rental then buy another residence in Charlotte. I would love some thoughts on a way to use the equity we have on out 2 property's to purchase the new home. 1031 exchange?, HELOC? Cash out refi? Hopefully this makes sense, Thanks for any help