Delete Security Question/Forgotten Password Challenge

Hi, I’d like to know if there is an API method that can be used to delete users Security Question that is used as the Forgotten Password Challenge

We have a number of users who have been migrated from Stormpath whose custom question is “StormpathMigrationAnswer” (or similar) and the users do not know what the answer is and are thus unable to complete password resets

We want to delete that question and ask our users to reset their own.