Changing angle of the mesh and lowering the floor in the middle of simulation

HI!

I wanted to change the angle of the chute in the after 8000 runs. Therefore I did the following
....
#the chute
fix cad3 all mesh/gran chute.stl 6 1.0 0. 0. 0. 0. 48.3 0.
fix movecad all move/mesh/gran rotate 0. 0. 0. 0. 0. 1. 7.0 cad3
......
fix granwalls all wall/gran/hertz/history 3 0 mesh/gran 5 cad1 cad2 cad3 cad4 cad5
......
fix ins1 nve_group pour/dev mass 3.888 10001 distributiontemplate pdd2 region bc massflowrate 0.5554 vol 0.6 20
......
run 8000 upto
unfix ins1

unfix cad3
unfix movecad
fix cad3_l1 all mesh/gran chute.stl 6 1.0 0. 0. 0. 0. 52.5 0.
fix granwalls_l1 all wall/gran/hertz/history 3 0 mesh/gran 1 cad3_l1
fix movecad2 all move/mesh/gran rotate 0. 0. 0. 0. 0. 1. 7.0 cad3_l1
.....

But this is not allowed as mesh/gran is not allowed twice.
Could you kindly tell me how to implement this logic!!

Simultaneously I would also like to lower the floor. Is it possible to do that, so that I dont have to simulate for reordering of the spheres on the floor after it is lowered. Say! decreasing the z value of all the particles with velocity zero!!

Regards,
TM