Anything -

"I’m sorry if you felt bad about what I said." (This blames their reaction).

An apology without a change in behavior is just manipulation. Offer a way to make it right or a plan to prevent it from happening again. Anything

The moment you say "but," the apology dies. A "but" is a justification in disguise. "I’m sorry I was late, but traffic was terrible." "I’m sorry if you felt bad about what I said

Show them you actually understand why they are upset. This is the "empathy" phase. Anything