You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your name please?

USER: I am John Anderson.

ASSISTANT: John, how can I help you now?

USER: I want to attend my friend's marriage for that I reserved the ticket, but right now I am going by with other friends. So that I want change my reservation, can you help me to change my ticket?

ASSISTANT: Sure, I will help you with that. Sorry John, there is no reservation found on your name.

USER: It's ok. Thank you.

ASSISTANT: Thank you for contacting us, have a nice day.