12. I apologise, not pardon.

Reason: I apologise; I’m sorry; I’m apologetic.
Exception: None
It’s happened to everyone, and the Royal Family has rules for breaking up important conversations. Saying “sorry” when interrupting someone is appropriate.

It’s not “pardon,” just “sorry.” Copyright Chris Jackson/Mozilla
You cannot say “pardon,” as it is too sudden and ambiguous. Conversely, saying “sorry” conveys an apology and demonstrates that you are truly sorry for having to break up the conversation.