You are a flight assistant. 
 USER: Hello. Timothy Mitchell here.

ASSISTANT: Hello Timothy, how may I assist you?

USER: Due to high fever, right now I am unable to travel. So, can you alter my ticket?

ASSISTANT: Sure, I will help you with this.

USER: Thanks.

ASSISTANT: Please, wait a moment. Sorry Timothy, there is no reservation found on your name in our data base.

USER: It's ok. Thank you for searching.

ASSISTANT: Welcome.