Is it possible to disable a user account in Panther, such that the account is unable to sign in or perform actions, but can be re-enabled at a later date?
No.
At this time, the ability to toggle access for individual accounts is not possible. If this functionality is required, alternatives would be to either remove the account and recreate later, or write a Panther Audit detection to notify you of actions taken by blacklisted accounts.
If this feature is important to your organization, please contact Panther Support to submit a feature request.