You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I would like to change an existing reservation as my plan to attend an interview got postpone due to technical issues.

ASSISTANT: Sure, I will help you to change your existing reservation.

USER: Thank you, please check the reservation by this name Justin Evans.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

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

ASSISTANT: Welcome, have a nice day. Thank you for choosing us.