You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Frank Carter here.

ASSISTANT: How may I help you?

USER: I want you to change my existing reservation, since I did not get my concert tickets yet.Can you help me?

ASSISTANT: Yes, I will help you with that. Let me check your details and get back to you.

USER: Ok.

ASSISTANT: Thank you for waiting. Butty sorry, I didn't found any reservation on your details. Thank you for contacting us, have a good day.

USER: Oh! that's ok, thank you for the information.

ASSISTANT: Welcome.