Second home vs investment property and 1031 exchange

[Son N.]

Hello,

I bought a condo (paid cash) near the bottom in 2010 and its current market value is quite good. My parents have been staying there rent-free but they have a new place and so we want to consider doing a 1031 exchange. Can I do 1031 exchange without renting it out first? If I rent it out, how long should I do it (i.e. IRS tax filing as a rental)? Is 1 year enough? Thanks for any guidance.