Custom absence types may be tracked in either days or hours, depending on your requirements and can be changed from one to the other by simply editing the absence type details.
To do this, go to the Administration section and then select "Absence Types" from the "Lookup Lists" panel and select the "Edit" option alongside the type you wish to change.
When the dialog box appears, you can change the tracking type from Hours to Days (or vice versa) and submit the form to make the change.
Note: If this absence type has an allocation, the allocations themselves will need to be changed for each employee. Any absences recorded in the system will already be recorded in both days and hours, so will display correctly.