Therefore leaving the principles of the doctrine of Chirst, let us go on unto perfection; not laying again the foundation of repentance from dead works, and of faith toward God, Of the doctrine of baptisms, and of laying on of hands, and of resurrection of the dead, and of eternal judgement. And this will we do, if God permit. - Hebrews 6:1-3leaving= having leftprinciples= word of the beginninggo on= be borne along; the Instructor being the Holy Spiritlaying again the foundation= Verb (kataballo) occurs in 2 Cor. 4:9; Heb 6:1; and Rev. 12:10. A comparison of all these passages (especially 2 Cor. 4:9 and Rev. 12:10) will show that kataballo and katabole are not the proper trems for founding and foundation, but the correct meaning is casting down or overthrow. Consistency, threefore, calls for the same translation in Heb 6:1, where, instead of "not laying again", the rendering should be "not casting down". That is to say, the foundation already laid, of repentance, etc, was not to be cast down or overthrown, but was to be left - and progress made unto the perfection.What kind a person is the author describing? This question must be answered before we can proceed further.I think the answer to your question is in the above 3 verses I have posted before v4. It seems that an understanding of the verses in hebrews after chapter 6 demand that you fully understand the 'principles of doctrine' of the 'foundation'. Especially because in v6 the writer mentions 'repentance' and in v1 it is clearly stated as a 'foundation' doctrine. It seems clear to me that the person spoken about is a Christian who has 'once enlightened' , 'tasted of the heavenly gift', and 'made partakers of the Holy Ghost'.