With CIT's BK (which I followed closely), they had two preferreds, "Series A" and "Series C". The C's had an optional conversion, while the A's did not.
On the same day that CIT announced their Ch11 BK they also offered an optional conversion of the C's to the common that was a great arbitrage play if you were fast. CIT's series A, which did not have the conversion option, was not offered a conversion. CIT's BK outcome was a complete equity wipe, yet strangely enough the government made off not too badly on their $2.3B investment, what with the $1.6B in student loan writeoffs and $1B in NOL reductions. (sorry for the CIT diversion, couldn't resist ;-)
I was original confused on this matter as the "prospectus" linked to on this board's front page points to the WAMU amended articles, which does not have the forced conversion provision. I can just tell that the lawyers are going to have a great time with this ;-)