Reassign task action is one of the Active Workflow Actions that can replace the task owner for a single task on the workflow timeline view. However, the task owner can not see this active workflow actions option to perform reassign the task.
Atomic Security is enabled which requires respect for the Atomic Security on Active Workflow Actions. In this case, the Reassign action's State Behavior is hide.
To solve this issue requires a system admin to follow the steps below to set up Atomic Security on active workflow actions:
- Navigate to Admin > Configuration > Object Lifecycles. Click into a lifecycle and then into an individual state.
- From the Atomic Security: Actions section, click Edit.
- Select Execute from the State Behavior picklist to apply the security setting to Reassign action.
- Optional: Click + Role Override to add an Expected Role to override the state behavior if the requirement is not to change the State Behavior.
Vault Help Documentation: Configuring Atomic Security for Objects