They should have handled it like Stargate (or Lower Decks):

O’Brien: “Haven’t we met before?”

Dukat: “I don’t believe so.”

O’Brien: “On the Enterprise, a few years ago. Someone who looks just like you but had a partial beard.”

Dukat: laughs “Oh, that guy. You’re not the first person to make that mistake. He’s nowhere near as handsome as me.”