Is there a polite and natural way to welcome the stranger you've already met today? A usual greeting seems inappropriate since you've already seen the person. Even if it was a brief encounter (in a pharmacy, in a grocery store, or somewhere at reception) and that person didn't remember you, is there a way to hint we've seen each other today?
Would 'again' be appropriate in this context?
Hello, it's me again.
Good/nice to see you again. (it doesn't imply this day, though)
What are other alternatives? How do you say it?