The motion to RECONSIDER allows a motion that was previously completed to be brought back for further consideration. It is, technically, a motion to reconsider the vote that was taken on a particular motion.
There is a time limit to what can be reconsidered. The motion to reconsider must be made on the same day as the motion to be reconsidered was voted on, or at the next meeting if that next meeting is part of the same series of meetings, such as in a convention of several days. The is also a restriction whereby if action has been taken on a motion, and that action cannot be undone, reconsideration is not allowed.
The motion to reconsider is a high priority motion, and can be made at anytime no one is speaking. However, the making of the motion is more important than the actual reconsideration. That is, if the motion to reconsider is made and seconded while another matter is pending, the chair does not place the motion to reconsider on the floor, but rather has the Secretary note that the motion to reconsider has been made and seconded. Then, when it is appropriate to do so, the chair returns to the motion to reconsider. Thus the actual reconsideration may take place at a different meeting that the one in which the motion to reconsider was made.
Reconsider must be moved by some who voted on the prevailing side of the vote. That is, if the to be reconsidered passed, that the reconsideration must be moved by someone who voted yes, if the motion to be reconsidered failed, then the reconsideration must be made by someone who voted no. It must be seconded, and requires a majority vote to start reconsideration. The motion being reconsidered still must pass by its own requirements of majority or 2/3.