You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Anna Edwards. Due to sudden change in the dates of summit which was going to be held in the place, I want to do some changes in my existing reservation, can you please help me?

ASSISTANT: Sure, wait for a minute.

USER: Ok.

ASSISTANT: Sorry Anna, no reservation found on your name. Do you want any other help?

USER: It's ok, no thanks. Thank you for your service.

ASSISTANT: Ok, thank you for contacting us.