When a task is set up to be completed. Once it is complete, there should be an area or section on that task for the person who completed it to sign off. This allows others to seek that person out if there is any questions or concerns in regards to the task.
For instance. There is a task for admitting a patient and within are making sure the consent form is signed, primary doctor is confirmed, the email address is confirmed and all previous medical records are received. So if the email address for that client is wrong we can search who signed it off and speak with that person.