I'd be pleased to elaborate!

You can switch ancillaries by having both generals in the same stack or city, so that they both show up under the army tab at the bottom. Right click on the general wiancillaryilliary you want to take. Click and drag the picture oancillaryilliary onto the portrait card of the other general. And there you go!

A couple caveats, of course. Each family member can only have 8 ancillaries. You can't have duplicate ancillaries. The retinue also seems to be loosely categorized, such as priests, accountants, slaves, etc. You can't for example, have 2 priests from 2 different temples. There are also a few ancillaries that are non-transferable. I don't have a full list, but they usuallyally those associated specifically with the faction leader, such as spymaster and tender of the royal backside. Probably wouldn't want to swap the last one around too much without washing his hands anyway.

As buildingsings, i meant to build up the family members, not the actual building. Poor choice of words, sorry. One of the functions of academies, scriptoria, and the ludus magna is that they all speed up the number of ancillaries awarded, sometimes to extreme levels. By placing several family members in a city with an academy, you can gain several ancillaries a turn to place where you see fit. The upside of academies is that you get a nicretinueue quickly. the downside is that there isn't always a nice diversity of ancillaries, and if you don't watch it, you can end up with tons of ancillaries and nowhere to dump them. Hope this helps.