To rewrite something means to write or type it again, often with changes or improvements. You might need to rewrite an essay after your teacher gives you feedback.
Rewriting can happen at any stage of writing - maybe you wrote a draft and didn't like how it turned out, so you start over from scratch. Or perhaps someone gave you some useful suggestions on what to add or change in your text, so now you're rewriting with their ideas incorporated. Sometimes people even rewrite articles they've written for websites or blogs to make them more interesting for new readers.
The act of writing again or anew.
Example: The film script underwent a rewrite for the European market.
To write again, differently; to modify (a piece of writing or music, etc.).
Example: The editor asked me to rewrite my article for a non-technical audience.
