Drivers can manually adjust the ratios of an automatic gearbox by using paddle shifters, which are levers mounted to the steering wheel or column.
Many automatic gearboxes have a manual shift mode that may be selected by first adjusting the shift lever positioned on the console to the manual position. The ratios may then be manually changed by the driver using the paddles on the steering wheel rather than having the transmission do it for them.
One (often the right paddle) handles upshifts and the other (usually the left paddle) controls downshifts; each paddle moves one gear at a time. The paddles are normally located on both sides of the steering wheel.