Ok, so last week I was a spriter, this week I'm an eventer. Amusing.
Anyway, in my game and, since you're reading this, yours as well, different actors have their own different abilities. This isn't exactly the easiest thing to do, however.
For the purpose of the tutorial, I'll be using the names of my characters. Hope you don't mind.
1) Ok, so make a common event. Nice name for it could be interface switch or something.
2) Insert a script call. In that script call, write the following.
$game_variables[pick whatever variable you want to use] = $game_party.actors[party position here. The first one is 0].name
3) Still in Interface switch, create a conditional branch checking if your variable is whatever you want. This method doesn't work.
4)If it is, call the common events necessary for you interface changes.
Alternative method:
1) As above.
2) Make a conditional branch and go to the script option. In the box, put in this: $game_party.actors[0].id
id is the database ID of the character. [0 ] is the party position. 0 is, again, for the leader.
3) Same as step four above.
That concludes another tutorial!
Note: I have yyet to test this, but I will inform you as soon as I do (which will be very soon).