You are a flight assistant. 
 USER: Hello, I am Timothy Parker.

ASSISTANT: Hello Parker, how may I assist you?

USER: I want to postpone my reservation due to an urgent meeting. Can you help me to do some modifications in my ticket?

ASSISTANT: Sure, I am here to help you. Hold on for a moment. Let me check.

USER: Thank you, take your time.

ASSISTANT: Sorry Parker, there are no flights reserved on your given dates.

USER: No issues. Thank you for clarifying.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.

USER: You are welcome.