You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: Myself Donna Roberts. Actually, my friend and I planned a trip to Houston in this weekend.So, suddenly my friend meet with accident I have to take care of my friend, so please do some changes in my reservation.

ASSISTANT: Sure Donna, let me check the reservation on your name.

USER: Ok.

ASSISTANT: Sorry Donna, there is no reservation on you name in our data base.

USER: It's ok.

ASSISTANT: Thank you for reaching us.

USER: Thank you for the checking.

ASSISTANT: Welcome.