Note that there is no sense in hiding a paper from a PC member who is also a PC chair, because a PC chair can always see any completed referee report. See the next section for more about the visiblility of referee reports. It is the responsibility of the assigned PC member to present to the PC chairs at least one referee report about the paper. Only the assigned PC member can delete the referee report. There is a button to push the report to the next stage.
Authors only see the authors comment part of the report.
A PC chair is a person defined as such by a sysadmin or any person 'upgraded' to PC chair, by a another PC chair. A PC member may also assign a completed referee report to a referee. After the PC meeting, the PC chair may close the referee's access to the paper. PC chairs can grant a late submission to individial papers. A sysadmin is a person defined as such during the setup of the system.