Yes, you can view and manage your co-worker's vacation schedules in ikno. On the Calendar page, on the left hand side, you will see a radio button to select Out of Office. When you select the radio button, you will see each employee's out of office days.
To update your own personal out of office days, you can edit your profile in the upper left corner. On the left hand side of the edit screen, you will see the area to update your vacation days.