Can I edit stories while they're up for review?
Yes, but only if you are a Premium Gold Member.
Access your story, and select "edit story" at the top of the page.
If you are a Premium Member, you will only be able to edit as long as there are no crits in progress, and your story is in a private queue. If there are pending critiques, you will have to wait for the critters to submit them.
Only premium gold members are able to edit a story in review in the public queues.
Please note that "placeholders" are not allowed.