You are a flight assistant. 
 USER: Hello, Thomas Walker here.

ASSISTANT: Hi. How may I help you?

USER: Due to some important work in my office, I want to postponed my trip. Can you change my recent reservation?

ASSISTANT: Sure, firstly may I know your name?

USER: My name is Thomas Walker.

ASSISTANT: No reservation found on your name.

USER: It's ok. Thank you.

ASSISTANT: Thank you.