When someone apologizes and then actually changes, the change was the apology. The words were the receipt.

Behaviour is the proof and language is only the paperwork. A sorry with nothing after it is a mood that passed; a change you can observe three weeks later is the thing itself, whether or not anybody made a speech about it. That is why some of the best apologies you receive are quiet, and some of the most eloquent ones are worthless.

Give people a month before you decide. Watch for the specific thing stopping rather than for better explanations. And when you are the one who got it wrong, spend less time constructing the sentence and more time not doing it again.