Once Articles of Incorporation for a 501(c)3 are in place and have designated a site to raise money for can these be changed? The by-laws state no, but can a new board change the by-laws to be able to change the Articles of Incorporation? If your 501(c)3 is set up to work for say a certain school can this be changed by a new board? Or is it set for this site only? Do the items that are donated and purchased with money from this 501(c)3 that is designated now for this site be taken away by a new board or does it all belong to the site? Not the board of a PTO!

I assume your bylaws define the procedure for amending the bylaws. So yes - if the bylaws prohibit something it is always possible that the board could follow the appropriate procedures to remove that prohibition, as long as it doesn't violate IRS provisions.

As for the articles of incorporation - as long as the charitable purpose of the organization remains charitable, then yes, they can be amended. Each state has its own rules as to the procedure for amending the articles of incorporation. So if the original articles and/or by-laws limit the scope of the charity to supporting one particular school, to expand that scope would require an amendment to either the articles of incorporation or the by-laws (or both), which would have to be approved by the board.