In case you skip it...

This episode reveals that the Vorta have a couple of traits that come in handy for a race of diplomats: they are immune to most poison and they are regularly cloned, making it easy to maintain continuity with their replacements when they die in the line of duty.

As such, the Weyoun who died in “To the Death” was actually the fourth Weyoun. He’s been replaced by the fifth, who is now the Dominion liaison and advisor to Dukat.