You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello,.

USER: I am Shirley Lewis.

ASSISTANT: How may I help you today?

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

ASSISTANT: Sure, please be on hold.

USER: Ok.

ASSISTANT: Thank you for your time.

USER: My pleasure.

ASSISTANT: We are regret to say that, there is no active reservation found in your name.

USER: It's ok, not a problem. Thanks for your help.

ASSISTANT: Thank you for reaching us. Have a great day.