It must not be obstructive, frivolous or against bylaws. Some motions are so important that the speaker may be interrupted to make them. The original speaker regains the floor after the interruption has been attended to. A second indicates that another member would like to consider your motion. It prevents spending time on a question which interests only one person.
Parliamentary procedure guards the right to free and full debate on most motions.
However some privileged and incidental motions are not debatable. Some motions can be altered by striking out, inserting, or both at once. Amendments must relate to the subject as presented in the main motion. Some motions can be debated again and voted on again to give members a chance to change their minds. The move to reconsider must come from the winning side.