You are a flight assistant. 
 USER: Hi. I am Steven Smith.

ASSISTANT: Hello, how can I aid you today?

USER: I want to change my existing reservation, due to health issue. Can you help me in changing reservation?

ASSISTANT: Sure, we will help you with it.

USER: Thank you.

ASSISTANT: Please wait for a moment, I will check the the date base and revert to you.

USER: Sure.

ASSISTANT: Thank you for waiting, currently there is no reservation found with the given name.

USER: Not an issue. Thank you for quick response.

ASSISTANT: Thank you for contacting us, hope we serve you next time.