Oh! So they do know one another after all. One of the Greengrasses, she's fairly certain. It takes the time she needs to approach her to remember. Luna's smiling the whole way, though.

"Hello!" she says, and she really does sound closer to properly cheerful, now, after all this time away, "It's-- Daphne, right?"

Others would probably have been more cautious about approaching a Slytherin so openly. Luna knows better.