You are a flight assistant. 
 USER: Hello. I am Brian Phillips.

ASSISTANT: Hello, how may I amend you?

USER: I want to modify my reservation due to prepone of my client meeting. Can you change my travelling dates?

ASSISTANT: Sure, please give me a moment.

USER: Sure.

ASSISTANT: Unfortunately we did not found any reservation with your provided name.

USER: Ok, thank you.

ASSISTANT: Thank you for connecting with us.