Do you give every chick you talk to so much say in the matter??
Me: Hey, come over tonight! I wanna see you.
Her: I unfortunately have to talk to my now ex-boyfriend, tomorrow? We can get fat and d&m about it?
Me: Haha, ahhh serious? You know how bored I've been after my operation - just swing around later tonight
Her: I unfortunately have to talk to my now ex-boyfriend, tomorrow? We can get fat and d&m about it?
Me: Well aren't you all tied up then!

. Tomorrow's fine, just text me early and let me know what you're doing, I might have some visitors/gotta head to the Doc's/shagging some other slut before you (whatever you like) Catch ya.
Most girls love when a guy is leading; it's an attractive quality after all. Be cheeky, funny, cocky, blunt, over the top, subtle, whatever, but lead the way! You're the man here, and we want to steer the ship in the direction of pussy town.
When you organise a catch up on your terms, whether a woman wants your dick or not, there's a subconcious level of value there. She's agreed to your conditions; there's validation. I mean, you're placing some sort of importance over the situation. You don't get any of that from leaving the ball in her court.
You don't have to become Rommel or anything, and I got no idea what the situation is like with this chick, but in order to avoid future friendzoning you
DO need to minimise your low-value interactions (which is essentially what's happening in your OP) and be more leading. Hope that helps