You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you?

USER: I am very happy to change my existing reservation because my examination was postponed, now I have much time to prepare for the exam. So please help me in modifying my recent reservation.

ASSISTANT:  Sure,Please wait a while.

USER: Take your own time.

ASSISTANT: Thanks for your time.

USER: It's ok.

ASSISTANT: We didn't found any reservation by this name.

USER: It's not a problem.

ASSISTANT: Can I know your name?

USER: I am Eric Green.

ASSISTANT: Thank you for choosing us.

USER: Thanks for checking.