You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I serve you at this moment?

USER: I want to change an existing reservation due to health issue, can you please help me?

ASSISTANT: May I know your good name please?

USER: Sure, my name is Emma Clark.

ASSISTANT: Ok, please wait for few minutes.

USER: Sure, I will wait for your response.

ASSISTANT: There is no existing reservation found on your name in our records. Thank you for reaching us.

USER: Ok, not an issue.Thank you for your information.