You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Ruth Green.

ASSISTANT: How may I assist you today?

USER: Due to my health problem I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Sure, I am here to help you, please wait for a minute to check the reservation details.

USER: Sure, I will wait for your reply.

ASSISTANT: Thanks for your patience, I could not find any reservation with your name in our database as per your request.

USER: That's fine, thank you for your help.

ASSISTANT: Thanks for reaching us and have a safe journey.