There is a debate among the Halachic authorities concerning the case of a person who is eating a food requiring "Boreh Nefashot" (such as a beverage, fruits, etc.) and in the middle of his meal moves from one room to another within the same house. The Shulhan Aruch rules that if the person cannot see his original location, and he did not intend to leave his original location when he began eating, then when he resumes eating he must recite a new Beracha. According to the Shulhan Aruch, moving from one room to another, from where one cannot see the first room, is no different from leaving the house, and thus if one moved to a different room while eating a "Boreh Nefashot" food, he must recite a new Beracha when he resumes eating. This is also the view of the Magen Abraham (Rabbi Abraham Gombiner, Poland, 1635-1682).
Other Halachic authorities, however, dispute this ruling, as cited and discussed by the Hafetz Haim (Rav Yisrael Meir Kagan of Radin, 1839-1933), in his Bi’ur Halacha. He notes that many Poskim do not consider changing rooms equivalent to leaving the home, including a number of Rishonim (Medieval Halachic scholars), such as Rabbenu Hananel and the Rif. The Bi’ur Halacha further observes that the situation in modern times makes it very difficult to follow the view of the Magan Abraham, requiring the recitation of a new Beracha every time one leaves the room.
In light of this debate, it is preferable when one recites a Beracha over such a food to have clear intent that he may leave the room at some point while eating, so that according to all views he would not have to recite a new Beracha when he resumes eating. If, however, one did not have this intention when he began eating, and he leaves the room while eating, he does not then have to recite a new Beracha, as we apply the rule of "Sefak Berachot Le’hakel" (we do not recite a Beracha in situations of Halachic uncertainty). This is the ruling of Hacham Ovadia Yosef, in his work Halichot Olam (vol. 2, p. 39).
Summary: It is preferable when one recites the Beracha before eating a food requiring "Boreh Nefashot" (such as drinks or fruits) to have in mind that he might leave his room and go to a different room while eating. But even if one did not have this intention, and he changes locations or leaves temporarily while eating, he does not recite a new Beracha when he resumes eating.
