You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I provide assistance to you?

USER: Can you please help me in changing my recent reservation? As my planned trip has been postponed to some other dates.

ASSISTANT: Sure, We are here to assist you.

USER: Thanks for that.

ASSISTANT: May I know your name to trace your details?

USER: Sure, my name is Emma Thomas.

ASSISTANT: Give me a minute.

USER: Sure, I'll wait for your response.

ASSISTANT:  Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: Oh! May be I did a wrong booking. Thank you anyways.

ASSISTANT: Thank you for choosing us.