For one person, it will be easier to open each family tree in different windows and copy/paste the information between them. You could try one of these options, but I wouldn't recommend it for one person:
-
Merge the two GEDCOM files (search for how to do this, there are programs that help with that.
-
Copy the relevent data from the FamilyScript file and paste it into the other Family Script file and import it back into FamilyEcho. If you do this, don't change any of the relationship data (parts of the line like this: mST5UG fBFD8J sEQ2U2 XISLS7 YEZ60B).