Partial release question

[Derek Cheng]

Hi
I purchased four properties under one mortgage two years ago. I am looking to sell one of them.  Lathe mortgage company told me it would be a partial release. (I hope that is the correct terminology). 

my questions are

1. Is that right term? The mortgage person didn’t give me much confidence. 
2. how does the payoff statement work?

3. They asked  for a payout statement with a 30 day good through date. Is that the proposed date of a sale?

4.What do I do with funds? Would it be a 1031?

thanks for your help