The Schedule in 10,000ft is based on the concept of availability. For example, John is available to the company for 40 hours per week. While availability may typically be the same for everyone in your company, sometimes people are unavailable for projects during a period of time. You can adjust the availability for each individual in their Profile.
Changing availability for an individual means setting a part-time availability block in their profile. Set the start date of this block to the first day you want them to show as unavailable, and set the end date to the last day they will be unavailable. Enter "0 hours" for Monday – Sunday in this part-time block. You do need to enter an end date, and you can always change this.
Utilization reports will show that this person is no longer available (i.e. available for 0 hours/day).