I think that the trigger you'll want is "Camera - Set Camera Field (Timed)", but I'm not 100% sure. I haven't dealt with cameras a whole lot before, and I've never tried to just change the distance or arrangement of the game camera before.
Here is how: Use the trigger "Set Camera Field (Timed) then you will see there is a choice: I think it is "Angle of attack" and there will be a player choice and an amount (Use negetive values) and it will say "Over ___ seconds" and that is just how long it takes it to change. I hope this helps...