If you go to Troy Meyers web site (
http://www.troymeyers.com/), you'll find very good and detailed instructions on deflasking orchid seedlings. I have never deflasked a single orchid, but the procedure should be more or less the same as for a full flask. I would leave the plant in the flask as long as possible, until the leaves hit the top of the flask, to maximize your chances that the deflasking will be successful. If the flask is such that you don't have to smash it and can just unscrew the top, do that a day or two before you plan to deflask so that the plant can acclimate somewhat to lower humidity and outside conditions. When you remove the plant from the flask, make sure that everything is clean - your hands, the surface you're working on, the potting medium, and anything else that will come in contact with the plant. Normally, there are many plants in a flask and they can be planted together in a compot where they "take care of each other" by keeping the humidity fairly high. Your single plant will need protection from drying out initially. I would probably pot in in a small pot (2" or less) with sphagnum moss. Once potted, the whole thing, pot and plant, can be kept in a plastic container to keep the humidity up. For a single plant, you might try a deep tupperware-type container with a lid or plastic wrap over the top. Every day the covering can be left off for a longer time until the plant is weaned from the high humidity situation. I used to use a weak fertilizer solution and/or SuperThrive when decompotting, but find that plants seem to do better without these additives.