Here is the situation; I made an article that got published in a Computer Science conference; the final decision was that it was considered a borderline paper. After a while I got an email from the organizers of that conference, letting the authors know that there would be the chance to resubmit our articles to a journal, but that the work should contain at least 30% more contribution than the original paper. Long story short, I worked through all the reviewers comments and added more information on my original article.
Actually I am a little bit afraid if my article would make it through the journal, but because I worked hard on doing the asked changes I would not like to leave it like that.
For that reason, I was wondering that in case of a rejection, Could I submit my expanded work to another conference; or should I just leave it like that? I am afraid that maybe the reviewers from another conference could see it like a case of self-plagiarized, even though I am citing my original article.
What to do in this situation? Should I paraphrase all the article again before submitting it with the new material? or should just let it be?