Promoted and moving to a new building but want to pursue a woman at work.

I (29 M) have had my eye on this one woman (23 F) since we went on a business trip to Missouri last summer. We work for a big company in the east coast so there are multiple departments. She joined me, and others, in Missouri because her boss wanted her to gain experience interacting with the-company-in-Missouri since it may become one of her duties when we return back to the East coast. I felt that we kicked it off pretty well and chatted a bit. There were several times where I felt she was being pretty affectionate and she even hinted in driving around sightseeing alone together.

Fast forward to now, we work out of the same building in the east coast and we continuously cross paths but she never seems to be by herself or the timing isn’t right to talk to her since were both working, and it seems that I’ll never get a chance to ask her out since I’ll be moving to a different building in the next few days due to a promotion. We exchanged personal numbers, but it was because we were on a business trip together.

She stated, “oh I don’t have your number saved” when we went to a baseball game, with others, on our last day there. But I sent her a picture of her ticket/barcode not even an hour before she said that. Maybe she was lying and trying to semi-shit test me? I want to pursue her because we seem to get along and I’d definitely like to get to know her better.

I’ve crossed paths with her everyday this past week and exchange the typical “hey, what’s up, what’s going on, how are you”. Should I call her on her on her cell, since she knows I have it, and ask her out or is that too direct? I’m clinging on the small chance that she’ll be in tomorrow (Saturday), and if that’s the case, she’ll more than likely be by herself and would have no problem striking a conversation with her at her desk. Never had this issue before and it’s bothering me that I can’t ask her out because there’s too many people around and I don’t want to “put her on the spot”. Any constructive advice is welcomed!

TLDR: moving to a different building at work and need advice on how to ask out a woman in crushing on, in a different department but in the same building. Have her number, we cross paths often, but the timing is never right since we’re at work.