Converting NYC Apartment Building to Condos - can it be done?

[Maura Paler]

We live in a 4 unit building that is currently apartments in NYC. 

The owner would like to convert to condo, but apparently this is a very tricky and expensive thing to do in NYC with tenants in place. If he is able to do this we would like to buy ours and possibly another of the units. 

Does anyone have any experience with this? Apparently the best way is for each of the four tenants to remain in their respective apt and each of us buys our individual unit, which is a possiblility. Otherwise the owner has to vacate the whole building to convert to condos, which seems bizarre and is certainly impractical. 

Any ideas would be much appreciated....thanks! 

Maura