To Reduce Speed While Using Cruise Control

WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

There are 2 ways to reduce your speed while using cruise control.

Move the cruise control switch downward to the SET/COAST position and hold until you obtain the lower speed you want. Then release it.
To slow down in very small amounts move the cruise control switch downward to the SET/COAST for less than 3/4 of a second and release. Each time you do this, you will go approximately 1.6 km/h (1 mph) slower.