You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I have planned to change my reservation due to sudden change in my trip, can you assist me?

ASSISTANT: Ok, may I know your name?

USER: Lisa Roberts.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Thanks for waiting, I have gone through the reservation list twice but could not find any reservation active under your name.

USER: No problem, thank you for searching.

ASSISTANT: Welcome Lisa Roberts.