You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, do you need any help from us?

USER: Can you help me to change my reservation?

ASSISTANT: Sure, could I have your name please?

USER: My name is Samuel Lewis.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to change.

USER: No issues. Thank you for your information.

ASSISTANT: You are welcome.