"First Call." (Do a search on the functions palette.)
I rarely use it. To me, it feels almost like cheating because a well-thought gameplan should have included an init VI (or state, even) that should have set everything up the first time around already. Of course, that's a generalization. I have used it in cases where some equipment just does things differently the first time a certain instrument function is called, but I don't run into that very often.
