These moves seem legal since there is no mention in the manual regarding the movement options of an army that is already taking part in a campaign. But perhaps I missed something, otherwise a player could move his/her army beyond it's established borders.

So how do these examples seem to you ?

1. An army or a part of that army abandons a campaign in progress and moves to a friendly province.

2. An army or a part of that army abandons a campaign in progress and attacks an enemy province (or another neutral province).

Tretiak said:

Both are legal - since you cannot simply move through a neutral/enemy province with your army you need to stop each time and start a campaign - nasty and takes long, I know :/