You are a flight assistant. 
 USER: Hello. I am Alexander Lewis.

ASSISTANT: Hello. How can I assist you?

USER: I need to change my existing reservation, as my scheduled football match got postponed. Please help me in changing?

ASSISTANT:  Sure, please wait I will check and revert you in a moment.

USER: Ok.

ASSISTANT: Sorry, no reservation was found on your name.

USER: Ok, no worries. Thank you for your service.

ASSISTANT: Thank you for availing us.