I usually book directly without a Travel Agent (TA), but I am not aware of any way to waitlist on a flight, (usually in a specific class) except using the services of a TA.

My TA just waitlisted an itinerary for me in Z class on UA, whilst I am holding a confirmed flight on another airline.

1) Is there any way to waitlist at UA without a confirmed reservation for each sector?

2) Is there any way to waitlist without ticketing?

3) Once I have a confirmed and ticketed reservation, can I waitlist for a lower fare class for example? (assuming change fees made this worthwhile)

thanks