Need assistance repairing a city

[Lord Tyrannikillicus]

I've been looking for a couple days now and found some people saying there should be a repair icon when you select a garrisoned unit, but I got nothing. Tried dropping supplies on the town and also using heal ability, no go. I've started second campaign in Italy and have several cities pretty low on health. Can anyone answer definitively how you actually repair a city??

[Private twinkle toe 1010011]

You have to use "repair" function. It's right near "heal" ability.