Final answer:
An igneous rock can become another type of igneous rock through subduction and remelting or through contact metamorphism, resulting in new mineral compositions and textures.
Step-by-step explanation:
To describe two different paths an igneous rock can take to become another igneous rock, we must consider the geologic processes that may transform them. One path an igneous rock can take is to be subducted back into the Earth's mantle where it can melt and later re-emerge and solidify as a new igneous rock. This igneous rock will potentially have a different mineral composition based on the chemistry of the new magma and the cooling rate. A second path involves the rock being exposed to high pressures and temperatures at such levels that they do not melt, but recrystallize in place, a process known as contact metamorphism. This process can also lead to the formation of new igneous rock.
Intrusive igneous rocks, like granite, are formed when magma cools slowly within the Earth, leading to large visible crystals. On the other hand, extrusive igneous rocks such as basalt cool quickly on the Earth's surface, resulting in fine grains. The transformation from one igneous rock type to another typically involves changes in mineral composition and grain size, dependent on the cooling rate and the environment in which the rocks are formed.