A task must be opened before any actions on the task can be performed.
Tasks
GetTaskByStageId
Select and lock the highest-priority task at given stage IDs with the GetTaskByStageId method of the ABBYY FlexiCapture Web Services API, returning its ID.
Selects the task with the highest priority and opens it for processing. The selected task is locked, which means it cannot be opened by other users.
