*Choose a private and neutral location for the conversation to ensure confidentiality and minimize defensiveness. *Use objective language to describe what you witnessed. *Explain how the behavior could affect the client relationship and the company's reputation. *Give your colleague a chance to share their thoughts. *Offer constructive feedback on how they might handle similar situations in the future.

I would pull the person aside asap after witnessing the encounter and suggest that he might wish to get in front of what might be blowback by having an explanation for what precipitated his conduct. If he says "what conduct?" I would say "pardon me, I must be mistaken. If he doesn't know what he did wrong, I wouldn't feel the need to help him out. If he explains the situation in a way that suggests there were mitigating circumstances, such as being provoked by the client's unprofessional behavior, then I would suggest writing a memory jogger with his side of the encounter. And perhaps suggest that he warn the boss so that the he isn't blindsided if he gets a call from the client. Keep in mind the customer is not always right.

Find a private, neutral setting to talk to your colleague, away from the client and other team members.Explain how their behavior might impact the client and the team. For example, “I believe that maintaining a professional demeanor is crucial for our reputation.”Give your colleague a chance to explain their perspective. There might be underlying reasons for their behavior that you’re not aware of.Offer constructive suggestions for improvement, such as role-playing difficult client interactions or discussing strategies for managing stress.Check in with your colleague later to see how they’re feeling and to reinforce positive changes.

Describe the Behavior, Not the Person Focus on the specific behavior that was unprofessional rather than labeling your colleague as unprofessional. This makes the conversation more about actions and less about personal character & Explain the Impact Help colleague understand why this behavior is an issue, especially from the perspective of the client or the team’s goals.

Exhibiting unprofessional behavior towards a client or any one else for that matter, in a professional relationship is a big NO. We can have disagreements or difference of opinions but that doesn't make it ok for us to revert with exhibiting unprofessional behavior. In the event of witnessing such behavior, it is important to talk and share your feedback and observations with them. It would help to share specific instances along with possible alternate ways of expression. The concerned may also be impressed upon with the fact that each employee is an ambassador of the organisation and such behavior reflects the perception of the organisations image and reputation in the larger external and internal remits.