I'm not sure about HDB flats.....but I think they it should be
the same as private properties where sale is concerned? If thats
the case, then you can't just put a name in or pull a name out (its
not like a company where you can insert and remove shareholders as
you wish).
Legally, for a property, its a sale. That means.....
The whole group of you sell the flat.....and the whole group of you
(except yourself) buy the flat again. Lawyers must be
involved...and they will want to see cash being transferred (just a
dud cheque will do). Stamp fees will apply, etc. I believe the
total process is 3 months (at least thats the case for private
properties).
You can own a HDB flat and condo at the same time....as long as you
live in the HDB flat and not the condo. But realise that you ahve
to declare to the government and bank that your condo is an
investment (which can sometimes mean higher than normal bank loan
interest rates, higher taxes, have to declare rental in your annual
income, etc etc).