You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER:  I got an appointment to meet obligates of United states but suddenly they went to another location on the same dates, can you please help me in flight ticket modification process?

ASSISTANT: Sure, please tell me your name.

USER: Sure, my name is John Hernandez.

ASSISTANT: Ok, please allow me a moment.

USER: Sure.

ASSISTANT:  Sorry, there is no reservation with your name in our portal to make changes.

USER: Ok, thanks for your help.

ASSISTANT: You are welcome, have a great day.