From: Winnipeg, MB
In my game I have a US regiment that was due to withdraw in about 3 weeks. I needed some more combat power in an island invasion in progress nearby, so on the theory of "use it or lose it" I loaded the regiment on an amphibious TF and sent it to help out with the battle even though its prep level was rather low. Some of the heavy equipment -- motorized support -- was slow to load, and since time was critical, I just left that behind and used what was already loaded.
Fast forward about a week of game time. The battle at the nearby island went well and finally that base was taken and all enemy forces eliminated. The small remnant of my regiment that I left behind still shows that it will withdraw in about 2 weeks. But the main part of the regiment says nothing about withdrawal. In order for the unit to withdraw properly, do I need to recombine it? Did I stumble into an inadvertent cheat where I could keep the combat part of the regiment indefinitely?
Typically, the unit commander is part of the last fragment of the unit moving. That fragment is the Parent Unit and the one you moved away should say UnitXXX/2. I think if you withdraw the Parent Unit the fragment on map will become the parent and you will still be on the hook for late withdrawal penalties.
No matter how bad a situation is, you can always make it worse. - Chris Hadfield : An Astronaut's Guide To Life On Earth