You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you at this moment?

USER: I would like to change my existing reservation, can you help me in that?

ASSISTANT: Sure, we are here to help you to change your recent reservation.

USER: Thank you.

ASSISTANT: On whose name, your reservation has been done earlier?

USER: Sure, the ticket has been reserved on the name Charles Rodriguez.

ASSISTANT: Thanks for providing your name, please wait for a while.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry to inform you that, there was no active reservation found on your specified name to change your reservation.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for choosing our service.