Jéssica,
Here is how to convert a program written in EP3 to EP2: Open the .es3
file in EP3, open a blank program in EP2, then manually copy or rewrite
everything you see in the EP3 program to the EP2 program.
Other than that, I feel quite certain that you will find no way to
automatically convert an .es3 file into something that will work with
EP2. But I would love someone to prove me wrong.
-- David McFarlane