I was reading the Investment Club Operations Handbook
recently (BetterInvesting), and I was hoping someone could
clarify two questions that I had:

(1) When there is a new member admitted or change to the
partnership agreement, how is the agreement actually revised
- meaning do you add an addendum page with everyone's
  signature, or do you re-create the whole document?

(2) In terms of taxes, the handbook says when a member
withdrawals, the withdrawal itself is a taxable event based
on their cost basis. But, this does not make sense to me
because all gain/losses, interest, dividends, etc are
already being passed through to the individual members based
on their proportional ownership. It seems this would be
double counting. For example, if a club had a 25% return in
year one and sold all investments and went to cash, the unit
value would rise from $10 to $12.50. The gains would be
passed through proportionately. If a member withdrew, why
would the increase from $10 to $12.50 be a taxable event
when the underlying securities transactions have already
been accounted for on the K-1? Am I missing something?

Thanks.