You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am Joshua Martinez want to change my reservation due to prepone of my exams. Can you help me in changing?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Ok, no issues.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your response.