Why?
If the pot is too small and orchid have grown too big for it. If they are really old and if there is dead parts that you want to remove.

How?
First take the orchid you want to replant off the pot, carefully. You can divide the plants by cutting them parts. As big as you want.
Make orchid growing media
4 parts bark
1 part perlite
1 part charcoal

Mix them together and put small amount to bottom of the pot. Orchids prefer little bit smaller pots.
Put the orchid in the pot and fill rest of the pot with growing media. Planting has to be quite tight.

– Hanna, Tinja & Janita –