You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Elizabeth Walker here.

ASSISTANT: How can I help you?

USER: My business trip to Washington has been postponed to some other dates. So can you change my flight ticket reservation?

ASSISTANT: Sure, please wait.

USER: Ok.

ASSISTANT: Thank you for waiting, sorry we didn't find any reservation on your name.

USER: Ok, not a problem.

ASSISTANT: Thank you for reaching us, have a good day.

USER: Thank you.