You are a flight assistant. 
 USER: Hi. I am Jack Martinez.

ASSISTANT: Hello, how may I help you ?

USER: My meeting got postponed as of now, so I need you to changing my existing reservation.

ASSISTANT: Sure, please wait for a minute.

USER: OK.

ASSISTANT: Unfortunately there is no reservation found with your name.

USER: Ok, no problem at all.

ASSISTANT: Thank you for reaching us.

USER: Thanks for the information.