You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Susan Campbell.

ASSISTANT: How may I aid you?

USER: Due to sudden changes in climate, I was fallen sick.So I would like to change my existing reservation. Can you please avail me?

ASSISTANT: Sure, I will help you. Please be on hold.

USER: Sure.

ASSISTANT: Thank you for your time. Sorry, we did not find any reservation in your name.

USER: Ok, no issues.

ASSISTANT: Thank you for your reaching us.

USER: Thank you.