My grandmother has a B2 visa to visit Guam. After her two week stay, she wants to visit her other daughter in California but she will have to go back to Philippines for a day because its cheaper to travel from Phil. to Cali. Can she still use the same B2 visa. When will she have to surrender her I-94? After the California trip?
As long as the visa is valid and permits multiple entries (not all visas do), I see no problem.