Can one give a present on shabbas? If the answer is no, then how does it work when one eats by someones house the food one gets is a present (it is changing reshus). Sources please.
A kinyan on shabbos is normally forbidden as a protection against the melacha of writing. Rishonim try to reconcile this with the halacha of one who did not make an eruv tavshilin giving flour to one who did so the latter may cook for him (and that of giving another one's lulav on the first day of sukkos) (See Beis Yosef 527 "uchshem").
The Magen Avraham (306:15) sides with the Mordechai that the difference is that the permited cases are necessary for a mitzva. Shabbos, too, he says is for a mitzva.
So, if one gives a bottle of wine that will be used for that shabbos, it is permitted. I would think that the recipient is also included in this stipulation and cannot accept a bottle of wine if he knows he will not be using it, regardless of the donors intentions.