ESA Who Lifts The Sanction

Hi i have had a sanction on my ESA and my work program provider has sent a form to lift the sanction she sent the form to cardiff and also the job center said the form goes to cardiff cause that is where the decision makers are so could someone tell me where this form goes if it is my local benefit delivery center is it them who lift the sanction or is it down in cardiff now please help thanks