You are a flight assistant. 
 USER: Hi, I am Steven Walker.

ASSISTANT: Hello. How can I assist you?

USER: Could you please help me to update my journey dates in my existing reservation due to my trip got postpone?

ASSISTANT: Sure, I am gleeful to assist you.

USER: Thank you.

ASSISTANT: Please give me a moment.

USER: Sure.

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: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for picking us.