Hello,
This sounds like a question I've been dealing with the past several months... if you want the details, it could be a fun search and would take you all over SGT. With that said, in my transfer which just went through last week and takes place in just under two weeks, I didn't have to fill out any applications. As far as an interview goes, can't tell you if that's going to happen or not. However, you're already in at Disneyland, so hopefully to your Casting person that will mean that you have already passed the initial tests and that you should still qualify to be a Cast Member. I would certainly stress your reason for wanting to get into Guest Relations. Make some contacts there as well, see if you can shadow a Relations CM for a day. That way, when you go to any interviews you may have to go to, you can go in knowing the job description and what you're in for.
Last week, I went to Animal Kingdom. One thing I like to do is make sure I always have Guest Service Fanatic cards on me... it's one thing the Cast Members are always able to accept, it goes on their record card that they did a good job, so I like to keep them with me. I was running low, so I went to Guest Relations at AK to pick up some more.
When I got there and to the front of the line, my first words were, "I have a
very serious problem, and I'm hoping you can help." It was great, I saw the guy's eyes glaze over a touch, but he never stopped smiling. You could see he was bracing. So when I told him what my *problem* really was, I'm pretty sure he almost fainted with relief. I hope that by doing that, by making a bit of a joke of what he has to hear every time someone comes up to that desk (because everyone's problem is a very serious problem, right?), I brightened his day a touch.
So, do you have any particular part of Guest Relations you are wanting to get into?
Oh, and one more very important thing:

to SGT from

and :wallaby: .
My opinions are mine and mine only. If my opinions are the opinion of others who happen to share whatever my crazy views may be, then fine, but it's not because I represent them in having my opinions. Got it?