Strategies you can use to avoid plagiarism:
Don't think of your report as “rearranging” or “changing” words and sentences or “adding” your own ideas. You need to find the most important facts, then start from scratch and explain them in your own way.
Imagine that you have been asked to explain your topic to a third grader. How would you pick out the most important pieces of information and explain it in a way he/she could understand? It may help you to actually explain it out loud to somebody, then write down your ideas.
Put ideas in your own words as you take notes. That means don't just “rearrange and change” what the author said. Don't write down words you don't understand. Use a dictionary to look up the meanings of unfamiliar words. Then use your notes as the basis to start from scratch to explain your topic. The idea of starting fresh is much different from “rearranging and changing” words from your source.
Compare your source of information to your written report to check for plagiarism.
It is essential for you to cite your sources correctly, but remember that citing your source doesn't give you permission to use or “rearrange” the author's phrases and sentences.