The two-year periods of ownership and use do not have to be at the same time. You have to have owned the home for two out of the five years before the sale, and you have to have lived in the home as your main home for two out of the five years before the sale, but they do not have to be the same two-year periods.
From the IRS web site: "You can meet the ownership and use tests during different 2-year periods."
Topic No. 701, Sale of Your Home
