Sell SFR and buy multi-family?

[Renny F.]

Hi there, I have 5 SFR and 2 duplexes (3 of the SFR are fully paid for with no mortgages). But I want to scale up and get into 10+ multi-family apartments. Should I sell the SFRs in order to buy the apartment buildings? Or do I keep them and refi-cash out and use that money to invest in the apartment buildings? Thanks for your advice!!!