It is possible for the admin to use the action "Answer" under a reply in a topic to tag it as "ANSWER".
But how can we undo that action?
(if it was a mistake click by the admin and there is no answer for the moment ;-) The "Answer" action is not displayed any more under the reply selected after clicking it by mistake.)
Why not let the "Action" remain in the possible actions, but with a "toggle" behaviour: set "ANSWER" / unset "ANSWER" ?
Customer support service by UserEcho