How do you greet customer in retail store?

If you know the entire situation that is upsetting to the customer you should greet them by saying something like, "Hello [thank you for holding], this is [your name]. I understand that [explain situation back to them as you understand it]." This gives them an opening to clarify any points that you have misunderstood. At this point you would begin whatever your company's protocol is for addressing customer complaints.

If you don't know why the customer is angry, you should greet them by saying something like, "Hello [thank you for holding], this is [your name]. Can you please explain to me what happened so I can help you?"