I've sat through literally hundreds of "notes" sessions after performing in improv shows.
A "note" is a comment or observation that a colleague or director shares with you after watching you perform, usually in a post-mortem meeting when the show is over.
Notes may be casual, corrective, constructive, or corrosive. A note can enlighten you, infuriate you, inspire you, and discourage you - sometimes all within the same note! Especially when you're coming down from the high of performance. That's why it's a great chance to show what kind of a performer you are - a professional.
To take a note like a pro, here's my two step advice :
1. Say thank you.
2. Stop speaking.
That's it. No arguing, justifying, debating, explaining, reacting, bargaining, re-wording, counter attacking, belittling, yelling, or being sarcastic.
Just say thank you.
It shows that you've heard the note.
Otherwise it turns the note into a little scene between you and that person and the rest of the cast become the jury. You want to stick up for yourself, I get it. You were thinking something during that scene and need to explain, I know. You'd like to ask what to do in that situation again, who wouldn't?
The thing is, the session gets caught up in that dialog and we all start to take a tally of the "good" and "bad" notes being distributed, and stop thinking about the show as a whole.
Say thank you and walk away. Then think to yourself - why did they give me that note? Think of it from their point of view. Think of it from the audience's and your fellow actor's points of view.
Think of it from your experience.
Then either talk about it further once you're calm and have thought about WHAT you'd like to clarify, pledge to try something differently the next time, or toss it out until it comes up again and becomes a theme.
It's something I learned as theatre etiquette from my high school drama teacher, and it's served me well since.
Allow yourself to receive before reacting. Say thank you and then stop speaking.
Your silence will sound professional.