If there is a good reason to rename a page, it should be done by using the "Move" link at the top of the page. (If you can't see the link, hold your mouse button over the little downward pointer labelled "More".) Copying the content of a page and pasting it into a new page is not an acceptable way of moving a page to a new title, because doing so loses the editing history, which must be kept to comply with Wikipedia's copyright licensing terms.