Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means ''change in form''. The original rock (protolith) is subjected to heat (temperatures greater than 150 to 200 C) and pressure (100 megapascals (1,000 bar) or more), causing profound physical or chemical change. The protolith may be a sedimentary, igneous, or existing metamorphic rock.

What's the best answer to this question: can a metamorphic rock become another metamorphic rock?
yes