You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Due to my health conditions, I want to change my recent reservation.Can you help me with that?

ASSISTANT: Sure, may I know your name please?

USER: Jennifer Roberts here.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there was no reservation found with your given name.

USER: No problem, Thanks for the information.

ASSISTANT: Thank you for choosing us.