You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER:  Due to sudden changes in the dates of summit which was going to be held in the place where I suppose to visit, I want to do some changes in my existing reservation. Can you help me in changing the reservation made on name Gary Taylor?

ASSISTANT: Ok, please give me a minute.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found with your name.

USER: It's Ok. Thanks for your information.

ASSISTANT: Thank you.