You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jacob Gonzalez.

ASSISTANT: What can I do for you today?

USER: I made my reservation in advance, but now found out I don't have any leaves so want to change my reservation.Please help me to change it.

ASSISTANT: Sure, please wait for few minutes.

USER: Sure.

ASSISTANT: There is no existing reservation found on your name in our records.

USER: Ok, thanks for your response.

ASSISTANT: Thank you for reaching us.