Toyota Repair: 1999 Toyota Avalon, toyota avalon, speedometer

Question
How difficult is it to manually re-calibrate the Speedometer? Also, what tools & steps are needed to do so?

Thank you for your help, it is greatly appreciated.

Answer
It's not something you or even technicians can manually do, if you're thinking of changing the odometer it's against the law in most states and must be done at an authorized repair station, if the speedometer is off it can be calibrated at the same facility, the dealers don't do this they would have to send it out.