You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Charles Evans.

ASSISTANT: How can I help you?

USER: I have done my reservation last week for my exams in Boston city but due to some technical issue in that university they have changed my exam destination to Houston city. Can you please help me to change my reservation?

ASSISTANT: Sure, just a moment please.

USER: Sure.

ASSISTANT: I am sorry no reservation found on your name.

USER: No issue with that one. Thank your for your quick information.

ASSISTANT: Thank you for choosing us.

USER: Most welcome.