I've done it with two brews. My winter brown ale and my IPA. The IPA needed time to condition and the winter brown could only get better with age, meanwhile I had other beers that were ready to drink, so I pulled those two. They warmed back up to room temp and sat at about 70+/- for 15 weeks. There is always the risk that some little bugs in there were being suppressed by the cold and could start to flourish at elevated temperature, but the alcohol and high concentration of CO2 are two factors that make it less likely.