You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello.

USER: I am Alexander Lewis.

ASSISTANT: How can I help you today?

USER: I have fallen sick due to bad whether, so I want to change my existing reservation. Can you please help me with that?

ASSISTANT: Sure, we are happy to help you. Please wait for a moment, I will check whether your reservation existed or not.

USER: Ok.

ASSISTANT: Thanks for waiting, unfortunately we did not find any reservation basis on your given name.

USER: Ok, no worries at all. Thanks for your kind information.

ASSISTANT: Ok, thank you for approaching us.

USER: Thank you.

ASSISTANT: Have a great day ahead.