recommission

verb

1. (transitive)To give a new commission or to validate an existing commission.
2. (transitive)To put back in service (undoing decommissioning).

   “They recommissioned the unused furnace, practically rebuilding it in the process.”

   “Hood explains: "It's never a case of just taking these units and dusting them down. Because they had been in storage, they had not undertaken their time-based overhaul, which had been due. They had also not undertaken their mileage-based overhaul, which was also due for all the sets. That caused a bit of a headache when it came to recommissioning them."”