If your users are using FindTime, they can now delete their data on FindTime.
NOTE this will delete all data (aka open/cancelled/completed pools) as well as their FindTime account. They will be able to relink their account with FindTime but the deleted data is unrecoverable.
To delete your FindTime data, you need to logon to your FindTime dashboard, available at https://findtime.microsoft.com/
Once logged on, access the Settings option (available top right of the pool list)
Then click the Delete all button and confirm the deletion process