Lance Corporal - Rank or Appointment?

My regular soldier grandfather was a Lance Corporal at the beginning of 1WW , therafter all references are to him as a Private.
His army records did not survive and so I assumed he lost his minor rank through some misdemeanour.
However, I now understand this may not have been the case - because L/C status was an "appointment", not a "Rank".
Can anyone cast light on this or comment further?
Thank you
cnb
His army records did not survive and so I assumed he lost his minor rank through some misdemeanour.
However, I now understand this may not have been the case - because L/C status was an "appointment", not a "Rank".
Can anyone cast light on this or comment further?
Thank you
cnb