How do you re- introduce a queen bee to a beehive?

If you were just to put the queen into the hive in the hope the other bees would accept her, they would almost certainly sting her to death because they are not used to her pheromones, so she would smell 'wrong'.

When a beekeeper wants to introduce a queen to a hive, any previous queen must be removed and the introduction of the new queen has to be done in such a way that the bees have time to get used to the her pheromones without being able to harm her. To do this, she is put into a special wire cage and the open end of the cage is plugged with sugar candy. The cage is then clipped into the hive between two honeycomb frames. The cage allows the queen's pheromones to spread through the hive. The bees will nibble at the sugar candy and after a couple of days the queen will be able to get out. By this time the other bees will have become accustomed to her pheromones and will accept her.