What's the best way to use equity?

[Elissa Williams]

My husband and I own two properties in southern CA, a coastal condo and a 10 acre ranch house outside the city. 

We have about ++$400,000 of equity between the two. 

The goal is to not sell anything, as both of them are cash positive and we'd like to hang on to them. Good renters, good locations, property values and rents are still rising. 

We've now moved to a different town we'd like to buy a duplex where we're living--I don't know what options we have to use equity in one of our properties as a down. Is this possible? Does it require a re-finance? 

We're good at buying and fixing properties up, but now in a market that requires large downs ($200k). 

So that's the question: With $400k in equity, what is possible? And what would you do if you wanted to get into a duplex that's $850k? 

Thanks in advance!!!