No, you shouldn't edit posts either, just make a new post. The issue here is that you didn't mention that you're entering as a LE in your new post (which you should have done because I as the manager can't go check all other tournament threads to see whether you had committed to play somewhere else. Or maybe I can?
Yeah, I can at least look at players that have withdrawn commitments). Anyway, you should not delete or edit posts because you're not allowed to take back a commitment. I think sometimes moderators go over these threads to check for deleted posts.