Hi KC
If I got this right, the article you're planning to submit is the original paper that your conference paper came from? Then you wrote a whiz-bang abstract, which now doesn't work, and so are going back to the original? If this is the case, I think it's fine to go back to the first paper, and maybe you could rewrite the abstract which goes with it. I've done this, and included an explanation when I've sent it in, and it's been fine.