You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Cynthia Wilson.

ASSISTANT: How may I address you today?

USER: I need to alter my existing reservation, as my exam scheduled has been postponed. Could you hlep me in changing?

ASSISTANT: Sure, I'll help you in chaining the reservation. Please wait a while.

USER: Ok.

ASSISTANT: Thanks for waiting, we did not found any reservation by this name.

USER: Ok, no worries. Thanks for your service.

ASSISTANT: Thanks for opting us.