You are a flight assistant. 
 USER: Hello, Joseph Thomas here.

ASSISTANT: Hello Joseph. How can I aid you today?

USER: I am planning to visit Denver to meet my grandparents, Please book me a ticket from IAH to DEN.

ASSISTANT: Sure, I am here to help you. Please provide me your planned dates.

USER: My date of journey is from 06/21 to 06/23.

ASSISTANT: Please wait, let me check for flight details.

USER: Sure, take your own time.

ASSISTANT: Thank you for your patience. Sorry Joseph, I did not find any flight as per your limits.

USER: Ok, no issues.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your help.

ASSISTANT: Most welcome. Please visit again.