When using a directional antenna, how might your station be able to communicate with a distant repeater if buildings or obstructions are blocking the direct line of sight path?

Radio waves at VHF and UHF frequencies behave somewhat like light and will bounce off hard surfaces such as buildings, water towers, and rocky hills. If a direct line-of-sight path to a repeater is blocked by an obstacle, you can sometimes point a directional antenna away from the repeater toward a reflective surface to "bounce" the signal around the blockage. Changing polarization will not help bypass a solid physical wall, and intentionally increasing SWR makes your antenna system less efficient. "Long path" is a global HF skywave concept, not a local VHF/UHF line-of-sight technique.