As far as I understand it, the recommended way to get an improperly flagged submission back onto the front page is to email the moderators and ask them to manually override the flagging, not trying to brute force it by re-submitting. The HN moderators can be reached at the email on the contact page linked at the bottom.

[dupe] This is a dupe. Discussion is there. No need to split it up. Flagged doesn't mean it hasn't been seen or isn't active, front page doesn't matter, stuff moves fast around here.