pdf command: should specify each engagement can only have one pdf

[kxyoke]

Initially I thought I could generate multiple pdfs (but to/from different permutations of people), but it turns out the pdf is replaced upon a new pdf command on the same engagement.

If this is intended behaviour, I think it may be a good idea to state it in the UG.
(Of course, it'd be even better in my opinion if I could create multiple pdfs for the same engagement :))