This is a good post but I would caution that if all you are doing is just rephrasing a source, e.g. per your example “I saw all of them at the event” with – “they all were present at the event” - doing that for an entire article would still be plagiarism even if it wasn't a word for word copy or something that @cheetah would catch. What you need to do is summarize and condense what the source is saying in your own words, not just swap out words here and there but otherwise basically write the exact same thing as the source but with slightly different word choice. Clearly and concisely summarizing a longer source is a skill and adds value to a post by presenting information in a manner that is easier to digest than wading through the longer original sources - while just swapping out words adds no value whatsoever and is still very much frowned on and flagged when noticed here.
Cheers - Carl
That's a professional talking, thanks @carlgnash for this great contribution. We keep learning new things as the day goes by.