P
You can request a Supersession on your claim, either ESA or DLA, when you believe as a result of a deterioration of your existing condition(s) or a new condition, that you would meet the criteria for a higher level of award.
As it is you the claimant, initiating the re-assessment, the burden of proof lies with, so you will need to provide significant new evidence, to support your request.
A Supersession differs from a appeal in as much as an appeal is concerned with your condition at the time of the Decision being appealed, whereas a SuperSession is concerned with you condition since that Decision.
I hope this explains it better.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
