Have your System Administrator complete the following.
Go to Setup > Property Options > General Information in RMS.
Navigate to the 'Reservations' tab.
Select the Default Arrive Time.
Select the Default Depart Time.
Select 'Save/Exit' to store the changes made.
Log out of RMS to allow the database to update with the changes made.
All reservations created in RMS will use the selected Arrive & Depart times as the default.