Passage, when engaged means the lock can be opened without the combination or key. Lockout, when engaged means the lock can not be opened with the combination. Think of a restroom, where you wouldn't want someone to walk in on you. However, the key over ride will still open the lock.Again, please make sure this lock is correct for your application as it is not reversible in any way. A lock with the key over ride is a must when there in only one entrance/exit.
Without the combination there is no way to know if the lock is operating properly. Combination it is a very involved process to reset the lock to accept a new combination.
Back be removed, the lock disassembled, the combination chamber removed and the tumblers reset. FYI, if they don't have the keys a locksmith can not just make a key.
The over ride lock core will have to. The item "Kaba Simplex R8100 Mortise Pushbutton Lock Over Ride Core Installed withKeys" is in sale since Friday, February 8, 2019.
This item is in the category "Business & Industrial\Building Materials & Supplies\Doors & Fixtures\Locks & Locksets". The seller is "bake98" and is located in Oxford, Pennsylvania. This item can be shipped to United States.