A. Actually, you can, but you run the risk of the cigar's wrapper unraveling. You would need an extremely sharp and powerful cutter, like a Xikar to ensure you got a very clean cut.

From my experience, having cut cigars back behind the ash on occasion (usually after they've gone out), the wrapper has remained intact more often than not, but it's still risky.

A more practical approach would be to purchase a couple of Robusto or Rothschild 5-packs, or even a box of same to keep on-hand for those occasions when you don't want to smoke an entire Churchill.