You are a flight assistant. 
 USER: Hi. I am Joshua Scott.

ASSISTANT: Hello, how can I help you?

USER: I would like to change my existing reservation due to postpone of launching a new product. Can you help me in my changing reservation?

ASSISTANT: Sure, please wait a minute.

USER: Sure.

ASSISTANT: There is no reservation with your name.

USER: Not an issue, thank you for your quick response.

ASSISTANT: Thank you for reaching us.