I entered stealth (or i think i did) previous round with a flurry along with my attack so i don't think a new entering stealth action is needed (not sure about the the results of my previous attempt though) so looking for necromancer while moving from a to b will require an action and a stealth roll since i want to stay hidden and an awareness roll on my part and if a flurry awareness will be having a -3 penalty"Entering" stealth is a combat action.
Moving while in stealth requires a separate roll.
I'd say that looking for someone specifically is an action, where just being generally aware of one's surroundings isn't.
I would say that if you're moving from A to B and while on the move, you're keeping a look out for someone, that's not a combat action, but just part of your move. However, if what you want to do is to find someone who is hiding in a place you can't easily see from where you start, that's a separate action.
But of course, this is a subject that's open to some interpretation by the ST. Regardless, unless you have some way of hiding reflexively, entering stealth at all requires you to spend your action on that.