You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can aid you today?

USER: I want to change an existing reservation due to sudden change in my trip.

ASSISTANT: OK, may I know your name to check your previous reservation in our database?

USER: I am Elizabeth Moore.

ASSISTANT: Elizabeth, please be on hold.

USER: Ok.

ASSISTANT: Thank you for waiting, there is no active reservation found under your name.

USER: Thanks for your help.

ASSISTANT: Thank you for contacting us.