Replace unit

From AgeofWiki

This tool can change a unit's type. To use it, select a unit, determine the proto name of the new unit and hit "Replace". (Proto names can be found out for example with this (http://aoe3.heavengames.com/downloads/showfile.php?fileid=87) patch or with reyk's list (http://www.nocheineaoe.de/proto3.htm).)

This is very handy for units that are used in triggers. If you simply delete them and place another unit instead, all the "Unit" settings in the concerning triggers will be lost. If you use this tool they won't.