You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Jessica Walker.

ASSISTANT: How may I help you?

USER: I want to change my existing reservation, due to heavy rain. Can you help me for that?

ASSISTANT: Sure, just a second please.

USER: Ok.

ASSISTANT: I am sorry Mr. Jessica Walker, no reservation found on you name. Thank you for reaching us.

USER: It's ok. Thank you for your help.