These are additional ideas to consider before you response to someone at work who is high conflict:

“You can train yourself to think, feel and say to yourself: “His comments are not really about me.” “The issue’s not the issue.” “Her personality is the issue.” And other short, quick sayings that train your brain to not react defensively.”
“Stay focused and not slip into reacting.”
“Focus on policies” not personal attacks.
If appropriate, acknowledge something related to the topic at hand that the person does well.
“Mention a reason or remind the person of a goal that is related to the main topic and that will make the recipient be seen in a positive light.”

For a full explanation of this approach and additional insight, please check out Bill Eddy’s book: https://www.highconflictinstitute.com/bookstores/biff