Query string to Permalink without a redirect

I have several posts on my blog. The posts are currently setup using query strings. I wish to convert my old posts to Permalink hopefully without using a 301 redirect. Since my old posts are indexed by the search engines I do not want to do a 301 redirect on hundreds of posts.

1] What’s the best way to do this?

2] Any plugin to help with this?

Any help would be deeply appreciated.