It's actually quite a simple process. Knowing the market is critical and knowing your tenants situation is even more critical. Have fun trying to evict an older person who has lived in the building for 30 years. Non-payment is the easiest way to get them out but not the only way.
We have a specific area we target and we are doing extremely well for conversion/flips and conversions to hold. Also, if you are financing your building pre-conversion, the attorney will need to apply for certain release provisions in the mortgage. Without that, bye bye conversion idea without refinancing. You want the best condo conversion specialists in the NY Metro area? Call me and we can meet with my attorney to discuss the concept. People in 2002 made millions doing this in Hudson. The timing is eerily similar today for that same opportunity and how the market is rebounding. Click on my link below to see an article I wrote about conversions in NJ.
Another thing to keep in mind is the "right of first refusal". That means, your tenants have the first chance to buy the units, before they are offered to the general public. So, if you are collecting rental income, you need to file with sufficient notice to your tenants, of your intentions of condo conversion. If you are going to be spend money on converting each apartment from "rental quality" to "condo" quality, it helps if you can prequalify you tenants for what will be a mortgage payment rather than a rent payment. Likely, if your tenants can afford the unit once it's improved and updated, if you work with them to improve their credit and ability to purchase the unit. On the other hand, if you have a mass exodus from the building, be sure you can carry the note completely on your own, without rental income to offset your carrying costs while you do work on the apartments and then subsequently sell them. Good luck and I hope this advise helped.