If you sold a property in 2019, it would be entered on your 2019 return next year. Did you set up the sale as a like-kind exchange yet? 

The first limit is that you have 45 days from the date you sell the relinquished property to identify potential replacement properties.  The identification must be in writing, signed by you and delivered to a person involved in the exchange like the seller of the replacement property or the qualified intermediary.  However, notice to your attorney, real estate agent, accountant or similar persons acting as your agent is not sufficient.

Replacement properties must be clearly described in the written identification.  In the case of real estate, this means a legal description, street address or distinguishable name. Follow the IRS guidelines for the maximum number and value of properties that can be identified.

The second limit is that the replacement property must be received and the exchange completed no later than 180 days after the sale of the exchanged property or the due date (with extensions) of the income tax return for the tax year in which the relinquished property was sold, whichever is earlier. The replacement property received must be substantially the same as property identified within the 45-day limit described above.

https://www.irs.gov/uac/like-kind-exchanges-under-irc-code-section-1031