Calling the automation method retires_on=(date) and passing nil for the date parameter will un-retire a VM. The retirement warning does not need to be changed as the code already checks for a non-nil retires_on value before warning. We should ensure this gets updated in the documentation.
We are in the process of re-evaluating all RFEs, for the short-term, anything in unspecified is getting set to a low priority. In the coming weeks, these will all be reviewed and re-prioritized to something that closer reflects reality.
Moving to the default assignee and status 'NEW' for triaging.