You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,. May I know your good name?

USER: I am Kimberly Allen.

ASSISTANT: How can I assist you?

USER: My friend reserved a seat for me on other dates unfortunately, now I would like to go on other dates. So, please change my existing reservation.

ASSISTANT: Sure. Wait for a while.

USER: Thank you. Sure.

ASSISTANT: Thanks for waiting.

USER: Ok.

ASSISTANT: There is no reservation found on your name.

USER: Ok. Thank you.

ASSISTANT: Thanks for choosing us.