Mizilus follow these steps:
1.The unit to be retrained must be in the province for one season.
2.Click on the train troops parchment to bring up the training queue.
3.Click on the unit to be retrained on the strategy map.
4.Drag the unit icon from the bottom of the screen to the training queue box.Trying to drag the unit game piece from the map will not work.
5.Next season your unit will be retrained with any upgrades availiable and if the appropiate dojo is in that province,ie retraining YS with a spear dojo,the retrained unit will bring a depleted unit to full strength.Replacing warriors costs koku so remember to keep track.Upgrading armor or weapons for full units costs nothing.So during bad harvest years you can still upgrade your full units.

------------------
Diplomacy is the art of telling someone to go to hell so that they look forward to making the trip.