Suppose you laid some tiles on the floor (e.g., a Chequered like the one you can see in the next image).
In case you need to change just one of the tiles and you do not want to apply again the pattern, you can get to the Navigation window, click the right mouse button over the tile you want to change, and select command Change tile->Single.
Select the new tile you want to replace this one with, finally tell the Application if you want to make the change on the floor only (Total wall tiles) or in the project (Total room tiles).
This article is valid for DomuS3D® 2017 and later versions