You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Gregory Martinez. Due to some personal work I want change my recent reservation, can you help me with this?

ASSISTANT: Ok, please wait for a while, let me check your reservation in our database.

USER: Sure.

ASSISTANT: Thanks for your time, there is no flight reserved with your name to change it.

USER: That's fine, not a issue.Anyways thank you for your valuable information and great service.

ASSISTANT: Thanks for consulting us.