What is a poem called that is another persons poem, same structure but you chang

Question:

What is a poem called that is another persons poem, same structure but you change the words and maybe meaning?

For example: You take one of shakespeare's poem keep the rhyme scheme and structure but change it into your own and may uses some parts the same. There is a name for this kind of poem but I don't know what it is.

Best Answer - Chosen by Asker:

sounds like plagiarism to me.