We have studied the effect of two simultaneous correlated white noises, one additive and the other multiplicative, on the activation rate of a bistable system. It is proved that as a function of the (positive-valued) correlation strength between the two noise sources the activation rate can be suppressed by orders of magnitude (likewise, with a negative-valued correlation strength it can be enhanced). Hence, the correlation between the two noises provides a tool for a controled slow-down (speed-up) of fast (slow) reactions by adding an appropriately chosen additional correlated noise force.21741763248252