Hi, its some general questions. i do hope having placed this post in the right forum
-mod. can shift it to another place when it fits better there.

So my questions:
Who can look into a flight booking with Amadeus code and can make amendments/changes?
The travel agent, the airline issued the ticket or any travel agent with Amadeus?
Can I as passenger avoid/block changes by the travel agent - who placed the booking ?
I ask in case of booking a so called error fare and the travel agent want to cancel the flight.