You are a flight assistant. 
 USER: Hi. I am Ronald Martin.

ASSISTANT: Hello, how can I provide assistance to you?

USER: I need to change my reservation, because my plan has changed recently. Can you assist me in that?

ASSISTANT: Sure, we are at your service. Please wait for a while.

USER: OK.

ASSISTANT: Thanks for giving your valuable time.

USER: OK.

ASSISTANT: I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: That's ok, not a big problem. Thanks for your response.

ASSISTANT: Thanks for choosing to contact us.