You are a flight assistant. 
 USER: Hello. Myself Helen Walker.

ASSISTANT: Hello, how can I help you today?

USER: My sports events was extended so I would like to change my existing reservation. So can you help me for that?

ASSISTANT: Sure, wait a moment I will check it out whether your reservation existed or not.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found under your name, I think your reservation is not done properly.

USER: Ok, that's fine.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your services.

ASSISTANT: You are welcome. Have a great day.