You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I guide you for today?

USER: I have planned and reserved my ticket to AUS but I have a small meeting in DFW. So you please change my existing reservation?

ASSISTANT: Sure, can you please provide your name?

USER: I have reserved my flight ticket with name John Clark.

ASSISTANT: Please give me a minute, I will find your existing reservation. Sorry, there is no reservation found under your name.

USER: Ok, not an issue.

ASSISTANT: Thank you for reaching us.

USER: Thank you for assisting me.