Just from reports view you can easily report missing work hours.
Simply by clicking on “Log Work” button in top right hand side corner or in report cell to report work for selected day.
Add Work Log from Report
Add Work Log on Behalf of Other users
Add work log for other user if necessary project permission is granted.
Make sure that project level permission Log Work on behalf other user in Team Worklog Reports application is granted. Check Team Worklog Reports - Administrator's Guide