Four MPU-6050 on the same I²C

Hello!

I want to use four MPU-6050 Sensors on the same I²C BUS. Is it possible to change the slave address of the MPU-6050? Is a change of the slave address permanent or must it repeated from switch-on to switch-on?

Or is it possible to multiplex the MPUs over the AD0-Pin (in running operation)?

Thanks!