You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Frank Hall.

ASSISTANT: How can I assist you?

USER: I want to do some changes in my existing reservation, can you help me for that?

ASSISTANT: Sure, please wait for a minute.

USER: Sure, I will wait for your response.

ASSISTANT: Hall, there is no reservation found with your details.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.

USER: Welcome.