Space Cover #452: Soyuz TM-24 crew replacementThis should have been a joint Russian-French mission named Cassiopee, flown by Gennady Manakov (commander), Pavel Vinogradov (engineer) and Claudie Andre-Desheys (scientist) – pictured on the card from CNES souvenir kit. One week before the launch (Aug 17, 1996) crew commander Gennady Manakov developed heart problems and on Aug. 12 it was decided to replace his and Vinogradov by back-up crew members Valery Korzun and Alexander Kaleri.
From this point the mission went as planned but... some of the souvenirs, especially the ones that already have been loaded into the spaceship had the names of the original crew. So not very common we can find covers that have Manakov and Vinogradov names as Soyuz TM-24 crew but signed by Korzun and Kaleri. Like German Komlev flown cover below.
Besides the rare stuff there were several fancy souvenir covers with nice stamped cachets like these below, produced by GeoGraph publishing house (G&G) and CNES philately club.