To be aware of s.t. [ka-/ta-]; to be conscious [ka-]; to inform or make s.o. aware of confidential information [ma-]; to make one's presence known [magpa-].
The pa--un imp. focuses on the one being allowed to regain consciousness. The pa--an imp. focuses on the one being informed about s.t.
If he becomes conscious later, give him some water to drink right away.