You don't, Someone does.
At this point it is Someone's responsibility to find the appropriate professional to fix the knife that they did not properly care for. This is assuming that Someone does not possess the skills to fix the knife themselves.
You don't, Someone does.
At this point it is Someone's responsibility to find the appropriate professional to fix the knife that they did not properly care for. This is assuming that Someone does not possess the skills to fix the knife themselves.