Subject To Addendum

[Brandon G.]

I briefly spoke with an RE attorney who advised me that most of the finer details of a transaction are worked out at the closing table. What I am curious to know is if that is the case, when purchasing a property subject to, would the subject-to addendum need to be signed "at the kitchen" table or is that something that is signed at the closing table?

I ask because the attorney seemed a bit surprised when I asked if they could write up an subject-to addendum for me, as if the addendum is just a minor detail. It didn't occur to me until now that perhaps he meant to say that it's something they take care of after the fact. 

Please advise