How do I change the requirement for walltime or for memory?

A: Use the condor_qedit command to change job requirements. Be aware of the fact that this change can be done only for jobs staying at Idle state.

condor_qedit <job_ID> MaxRuntime=86400
condor_qedit <job_ID> RequestMemory=4G
condor_qedit <job_ID> RequestDisk=30G