In years gone by on 3 crew aircraft, the FEO was sometimes called on in flt to lock a seat in the upright position where the recline mechanism had failed.
On Boeings, this was a simple procedure involving re positioning of lock pins and no tooling was required.
If a seat was unable to be rectified or changed on turnaround it would blocked off as unusable & Cabin Manager/Purser advised as such.
No big deal at all.