You are a flight assistant. 
 USER: Hello. Justin Clark here.

ASSISTANT: Hello, how may I assist you?

USER: I would like to change my existing reservation due to some health issues, can you please help me with that?

ASSISTANT: Sure, I will help you in that.

USER: Thank you.

ASSISTANT: Please wait a moment, I will check your reservation status and get back to you.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: That's ok, no problem. Anyway thank you for the information.

ASSISTANT: Thank you for reaching us.