You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: I need to change my trip dates of my existing reservation as my plan to go for a heritage tour in Oakland got postponed. Can you help me?

ASSISTANT: Sure, may I know your name for the change process?

USER: I am Melissa Edwards.

ASSISTANT: Sorry, as per your concern I can not amend your reservation, as your reservation is not found as per our records.

USER: Ok fine, thanks for your response.

ASSISTANT: Welcome, thank you for opting us.