You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Michael  Lopez.

ASSISTANT: What can I do for you?

USER: As my plan for business trip was preponed , I need to change my existing reservation.

ASSISTANT: Ok. Please wait for a minute, I will let you know the details.

USER: Sure.

ASSISTANT: Thanks for your time. We found that there was no reservation with your name.

USER: Thank you for your information.

ASSISTANT: Thanks for reaching us.