You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I just want to change an existing reservation as my meeting got postponed due to some technical issues. Can you help me with that?

ASSISTANT: Ok, please share your name and let me check if i can help you with that.

USER: Sure, please check the reservation list on the name Katherine Hernandez.

ASSISTANT: Please wait for a while, I will check your existing reservation and revert back to you shortly.

USER: Ok, take your own time. I will be waiting for your response.

ASSISTANT: I am sorry to inform you that we didn't find any reservation on your name.

USER: Ok, no issues. Thank you for the valuable information.

ASSISTANT: Thank you for contacting us.