You are a flight assistant. 
 USER: Hello. Alexander Hill here.

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

USER: Actually I have planned to attend the client meeting at Oakland, but due to some technical issues the meeting has been postponed. Help me in changing my existing reservation.

ASSISTANT: Sure, we are ecstatic to help you. Please wait for a while. I will check the reservation list with airline data and let you know.

USER: Sure, I will wait for your response.

ASSISTANT: Thanks for your valuable time. Sorry to inform you that there was no existing reservation found on your name.

USER: Not an issue, Thank you for your fast response.

ASSISTANT: Thank you for consulting us.