Originally Posted by theblahmaster
One thing I have learned though is that you can't "reinforce" units perse, but you can retrain units that have been damaged. Simply plonk them into a province where you can train units, open the training units box, click on your army, drag said unit into the box and viola! In 1 turn your unit has been reinforced and will have any extra upgrades on it (from armoury or swordsmith). Not sure how useful it is as you still lose your honour and such, but I learned something new through trial and error!