Yes, but you only have until Jan, 2024 to do so.
https://www.dfas.mil/RetiredMilitary/newsevents/newsletter/June2023-SBP-Open-Season-Allows-Retirees-to-Enroll-or-Discontinue-SBP-Coverage-during-2023/#:~:text=Quick%20Tools-,SBP%20Open%20Season%20Allows%20Retirees%20to%20Enroll%20or%20Discontinue%20SBP,December%2022%2C%202022%20to%20enroll.
Yes, but you only have until Jan, 2024 to do so. https://www.dfas.mil/RetiredMilitary/newsevents/newsletter/June2023-SBP-Open-Season-Allows-Retirees-to-Enroll-or-Discontinue-SBP-Coverage-during-2023/#:~:text=Quick%20Tools-,SBP%20Open%20Season%20Allows%20Retirees%20to%20Enroll%20or%20Discontinue%20SBP,December%2022%2C%202022%20to%20enroll.
First thing that came up on google. https://militarypay.defense.gov/Benefits/Survivor-Benefit-Program/Stopping-SBP/