A girl I used to fuck around with from school has joined my company. It's a relatively large company so we won't see each other day to day, but we could still run into each during company events and alumni networking events.

We had a somewhat rough falling out a year ago with me denying her a relationship and her taking it personally by blocking me on everything. No contact since.

Question: How should I approach this situation? I plan to be cordial and friendly when I eventually run into her at a firm event. I already know to not shit where I eat, but what happens if I already fucked this girl before?