Step 1
Click on the task in your Action Centre

Step 2
Click on the desired stage in the workflow bar

If you jump to Completed, the task will disappear from your Action Centre and be archived on the property's task timeline.
Click on the task in your Action Centre
Click on the desired stage in the workflow bar
If you jump to Completed, the task will disappear from your Action Centre and be archived on the property's task timeline.