It's fairly difficult. You would have to take apart both panels and the swivel parts to access the inside panel and repair it. If you need someone to repair this feel free to contact JoesGE. https://www.joesge.com/pages/fix-beats-by-dre Thanks!
NEVER use superglue to try and fix these. From all the Beats customers send into our repair center., the ones that have been super glued cause issues. Theses issues range from destroyed hinges or glued in wires which just cause more hassle. Currently the headband repairs aren't too expensive. Studio 1 headbands are $60 and Studio 2 headbands are $70 to repair. You can send them into Joe's to get repaired within one day. https://www.joesge.com/pages/fix-beats-by-dre