What to say – the first approach
Here’s what I’d advise: Make your way to her in a way that doesn’t seem unnatural or like you’ve made a beeline for her. Ask her – or her and her friends – a question about the place you’re in (e.g. Does she know what this song is? Where’s good to get food here? You just got here, what did you miss?) and make sure it’s with a smile.
She will almost always respond politely. If she doesn’t respond politely, you’ve done nothing wrong and that’s on her. Give a warm response when she does – say thanks, or agree with her, or even disagree with her if you can do it playfully.
Then make your excuses and leave her alone.