Is it possible to add a micro that will automatically send rows from 1 sheet to another once a completion date in a colum has been reached?
There are third-party solutions, like Zapier and Azuqua, that are able to handle that sort of things. Check out a previous discussion here: https://community.smartsheet.com/discussion/moving-rows
And API solutions...
http://smartsheet-platform.github.io/api-docs/#move-row(s)-to-another-sheet