Small Engines (Lawn Mowers, etc.): unlock motor, riding lawn mower

Question
my sister has a riding lawn mower and the motor is locked  up. How do you unlock motor I have never done that befor.Thank you for any help you can give me.  Beverly

Answer
Before you spend any time trying to unlock the motor, you need to determine what happened.  Is it out of oil?  Any noises before it locked?  If the motor is locked up, there is little you can do besides removing it and inspecting for what happened internally...and rebuild if necessary.  Hope this helps.