You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I benefit you?

USER: Due to sudden change 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 exiting reservation. Can you please help me out with this?

ASSISTANT: Certainly, I can help you out with that. Please let me know your name to check the data base and revert you.

USER: Sure, Reservation was done by the name Janet Harris.

ASSISTANT: Ok, please give me a minute.

USER: Sure, take your time.

ASSISTANT: Thank you for being patient.

USER: It's ok.

ASSISTANT: I have gone through the reservation list twice but could not find any reservation by the name you provided.

USER: That's fine, thanks for the response.

ASSISTANT: Thank you for approaching us.