code refactoring , need help to change the code

I have a a class which is used to create XML Nodes

like it contains function writeImageNodes, writeTextNodes, writeAttributeNodes, writeRootNode,....

Node I have new Requests that we should be able to the same data in different formates. Like JSON and HTML

Is there any Design Pattern which I can read to find the best possible solution for this, as there may be later some new formates