3 months old vanilla orchid suddenly caught rot
 

Hello, I am from Indonesia. I have just realized that my 3 months old vanilla orchid suddenly started to rot from the base.

this orchid is part of 50 vanilla that I bought 3 months ago to start small vanilla plantation on my garden. I mishandled them, put them in too much shade area and about 20 of them died from black rot. since then, I have put them in the suitable environment and they have grown very well in this past two months.

But suddenly, this orchid started to rot. it is about 40-45 cm tall. my question is:
1) Should I cut the rotting base and repot it to another pot?? but the rotting part is dry when I pinch it. Will it be okay to leave it as it is? I dont know when this rot started to develop since i havent been examining my orchid closely lately
2) this orchid share its pot with another orchid. should i repot it to? if yes, could they share pot together again?

thankyou very much for your help

Generally speaking, you should not put more than one plant in a container to avoid the possibility of them sharing a pathogen.

As for that plant, I'd remove the damaged part, with a good margin, dip the wound in cinnamon powder to seal it and protect it (cinnamon is a fair bactericide and fungicide), and go on from there.