Q: Our church has been using a temporary altar, but we are acquiring a used altar from a church that has closed. Does the bishop reconsecrate the new altar?
A: No reconsecration takes place.
Let me give you examples of what is not taking place so that you can see the values.
In the case of the dedication of a church already in use, the bishop sprinkles the altar with water if the altar is completely new on this occasion (ODCA III:9). This implies that if he’s using a previously consecrated altar repositioned in this church, it doesn’t even get sprinkled with water. Its consecration still endures.
Similarly, when a church or chapel is being “blessed,” then an altar that has already been blessed is not blessed again (ODCA V:22 and CB 968).
Sometimes not doing something gives greater honor than doing something.