Henry Pollard asks an interesting question and provides an equally interesting answer:
Have you ever been to a softball game where your partner didn't show up or didn't know what to do? Have you been assigned a one-umpire game and were afraid you might not be in the correct position or make the correct call? The latter is happening quite often, and I can guarantee you that before you hang up your umpire gear, the first will also occur.
We certainly do not advocate or encourage using one umpire in calling games. But if it is necessary, it can be accomplished with a certain degree of efficiency. You'll find the rest, of course, inside.