How to change the learning rate in the middle of training?

I am using reduce LR on Plateau scheduler to reduce the learning rate, i need to reset the learning rate, once it reaches 10^-6.
Does adding below line helps???
optimizer.param_groups[0]['lr'] = 0.0001

Yes, that would be the gist of manually setting LR.

for group in optimizer.param_groups:
    group['lr'] = lr