Yes you can and in many cases you should. You will very often find that individual coverage, if you can qualify for it, is cheaper than adding dependents on to your company plan. Because company plans generally cover everyone regardless of health condition they must charge more knowing that some people will use a lot of medical care.
Individual plans that require approval can deny coverage to those who they know will use a lot of care, thereby offering lower coverage to those who are healthier.
This is not true in ''all states'' since some guarantee coverage to everyone even on individual plans. It may not be fair either, but that is the way the system works in most states.