Somewhat like a 1031 exchange. See IRS Pub 544 page 32 ff. You will show the date of the condemnation as a sale date on the old property in Screen 22.  You will add a new rental in Screen 18 and you will show a new property with a new adjusted basis in Screen 22. If there is a passive loss and carryover for old rental, leave it there for this year and make a note to delete next year and tie the passive loss from it to the new property.

Compute the gain and report like a sale in Screen 17. I would simply describe as "Involuntary gain on [description of property] and show as a 4797 disposition following the examples in Pub 544.