cellio | daf bit: Bava Metzia 9

A mishna on today's daf talks about acquiring property through an agent, and this leads to a discussion in the g'mara. The g'mara discusses gleaning the corners of a field, which by torah law must be left for the poor. If a man gleans and says "this is for that (specific) poor person", R' Eliezer says this is permitted but the Sages say he must give what he gleaned to the first poor person he sees. In the end it depends on who is gleaning. If a rich man is gleaning for a poor man, the sages say that he couldn't acquire the gleanings for himself and so cannot then transfer ownership to another. If a poor man gleans for another poor man, however, all agree that he can bestow ownership on the other person because it was his to give away. (9b)

The difference isn't that R' Eliezer was talking about a poor man and the sages about a rich man. Both were talking about a rich man, according to the discussion, but R' Eliezer's argument was based on the idea that he could give away his property and become poor, at which point he would be eligible, so against this possibility he could be an agent. The sages appear to be more concerned with current state; they don't outright say "so let him do that and then we'll discuss it again", but to my reading it's implied.

(Today's daf is 10.)