A word meaning "To bring out of retirement" / "To bring back into use"

• (Re)instate? -- Seems too specific.
• (Re-)employ? -- Seems to apply to both machines and people, which is useful. But re-employ seems too general.
• Activate? -- Seems most appropriate perhaps, although for soldiers (people in general, even), you would say "return (them) to active duty" rather than "activate (them)".

In fact, the term that I'm looking for would be appropriate to machines and people coming out of, shall we say, a torpour of sorts.

Any ideas? The original phrase is a bit clunky, and I suspect there may be an alternative.

Solution 1:

When Michael Jordan first retired from basketball in 1993-94

he rejoined the Bulls in 1995 and led them to three additional championships in 1996, 1997, and 1998...
Jordan retired for a second time in 1999, but returned for two more NBA seasons from 2001 to 2003 [...] Despite his January 1999 claim that he was "99.9% certain" that he would never play another NBA game, in the summer of 2001 Jordan expressed interest in making another comeback

Wikipedia

Therefore coming out of retirement, you are said to rejoin the workforce; to return to work, or if you are a particularly well-known or famous in your field, making a comeback.

For a machine that was no longer being used you could say, it is back in working order. TFD

From The Portland Daily Sun

Monument Square Clock back in working order
Time is no longer standing still for the Monument Square Clock. The hands of time are moving once again at the historic clock, which was installed in Monument Square in 1975, after the Portland Rotary Club stepped forward to raise the money needed to repair and restore the timepiece. The Portland Rotary Club showed off the newly renovated Monument Square Clock on Thursday and presented Mayor Michael Brennan with a key to the clock.

Solution 2:

Reinstate, re-employ or reactivate would all work for people, machines, processes etc.

They all see usage in this context currently.