I don't often get flaked on by a first date so I'm not too practiced at dealing with them. I based my response on a few things I've seen on here.
Had a date set up for Tuesday night with a HB8. Pretty standard method of game was used, normally quite successful for setting up dates. I hadn't texted her in a couple of days (potential mistake). When on Tuesday lunch she sent me this.
HB8: Have you made many arrangements for later? I am so sorry but can we rain check?! I completely forgot I'd agreed to meet 3 friends who are up from ***** tonight!! We'd arranged it in June and I hadn't written it down

if it's a massive issue I can sack them off but if we were able to rain check to next week that would be AMAZING and I'd love you forever!
Me: Yea I'd made a few arrangements but that's no problem! Go out tonight and have fun
HB8: I really am so, so sorry! I am normally really organised!!
Me: Sure you can make it up to me next week!
(I remembered that next week is epically busy for me so before she replied I texted)
Me: Or maybe not...Turns out next week is pretty full on for me with Dublin and the event I'm organising! This ain't looking good to be fair
HB8: Well I would completely understand (even if you weren't busy next week) if you didn't want to meet me. I'll leave the ball in your court and you can contact me if you'd still like to meet at some point when you have more time

again, I really am sorry about tonight. I feel like a complete bitch now!
That was yesterday and I've not replied as I wanted to work out if I actually could find the time and if I wanted to meet her. Plus it seemed like a good moment to become scarce and make her wonder.
Now it looks like I have an evening free next week...How should I handle this? Should I text her tonight or leave it for a few days and let her think Im no longer interested?
Appreciate any feedback guys
Dave