Does anyone know how to correct the issue where you are not able to enter time after you unapprove timesheets? This is for an employee without a timesheet.

In error, I approved timesheets for all employees instead of approving for one employee. I was not able to enter time for another employee for the same period. I unapproved the timesheets, but I am still not able to enter time. There is no timesheet to unlock for the period.