The most obvious way to change gravity is to move to somewhere with a different gravitational field strength.
Another way is to set up an accelerating frame of reference. A linear accelerating frame of reference (such as a rocket or jet, or a controlled nearly free fall) would be somewhat expensive and demand a lot of space. A rotating frame of reference would be a more practicle method of increasing the gravity sensed by the pendulum - providing the radius of rotation (within, say, a cetrifuge) is much greater than the length of the pendulum.