The number of hours you are required to work each pay period
In order to complete a rotation you must complete the required number of hours within a three month period. How you are able to schedule your time is up to you. In order to get an excused absence you must notify your department supervisor for the internship.
Position may be being held for internal employees or there was once a budget/plans to fill the position but a change on the floor or with leadership occurred which caused hiring for that position to be put on hold or canceled. Depends on the unit.