How to change solenoid pack on 99 Plymouth Breeze A604 . Code reader says it is bad. Thanks.?

before i replaced it id have transmission shop look the car over and drive it,sometimes a scanner will pick up an old code,when their really isn't anything wrong with it,if it is bad let a transmission shop change it,they will have to change it and then clear the code,and make sure there's no other problems with it,that would be the best on this one,good luck on it.