The person who should take action on this defect is the tester who wrote the defect report. This is because a defect report in the "returned" state means that the defect has been rejected or sent back to the tester for further clarification or investigation. The tester who wrote the defect report should review the feedback from the developer, the project manager, or the defect triage team, and take the appropriate action, such as providing more information, modifying the defect report, or closing the defect. Defect Reporting - ISTQB not-for-profit association References: Certified Tester Advanced Level Test Manager (CTAL-TM) - ISTQB not-for-profit association, ISTQB Test Manager Certification - ISTQB Exams Worldwide - ISTQB Official Registration, Defect Reporting - ISTQB not-for-profit association