How to transfer a platonic, one on one dinner into a pick up?

Hey all, this is my first time posting here, so hi.

(hopefully this is the right board )

I'm visiting my hometown again after spending a few years away from it, and I am planning to have a platonic dinner with an old high school friend of mine, and want to try and elevate it.

I've had moderate success in bar's and clubs, but I have never really found myself in such a position, so I was wondering if anybody had any tips to help me out.

There are no specifics, so we may be having dinner at her place, or at a restaurant (hopefully her place), and it's completely one on one, so I won't need to worry about any approach or openers. Also, we had a brief romantic history several years ago, so I believe some groundwork has already been laid out.

Any help, or experience is appreciated.

Thanks,
Captain