here we create specific qos:
sacctmgr create qos max400cpu
sacctmgr modify qos max400cpu set maxtresperuser=cpu=400
sacctmgr modify user name=UserName set defaultqos=max400cpu qos=max400cpu
if there are any jobs queued, we need to change qos there too:
scontrol update job=123456 qos=max400cpu
sacctmgr create user name=UserName account=AccountName