sudden temperature change

Dear lammps developers,

I am trying to make a sudden change of temperature on a group of atoms which means that for example I want the temperature to be 160K for 500 (ps) and then it drops to 100 K for the rest of time. (acting like step function).I used “fix langevin” thermostat and set the temp to 160 K and run it then used another fix langevin to change the temp to 100K but the problem is it can’t change the temp can I do this in lammps?

Thank you for your time.
Best regards,

You can use the velocity command (between runs) to set
the temp to whatever you wish. If the system is not at equilibrium,
then it will change temp (sometimes rapidly) when you begin a run.
There is nothing you can do about that. You can look at the
fix temp/rescale command. It will change the temperature as
dramatically and often and unphysically as you like.