All 3 Uses of

dispose
in
The Phantom of the Opera

At the end of this clause, a line had been added, also in red ink: 'Box Five on the grand tier shall be placed at the disposal of the Opera ghost for every performance.'
Chpt 3 *

disposal = command

You must give me back my private box; and I wish it to be at my free disposal from henceforward.
Chpt 7

All the same, I should like to take advantage of the fact that you have not yet turned Christine Daae out of doors by hearing her this evening in the part of Siebel, as that of Margarita has been forbidden her since her triumph of the other evening; and I will ask you not to dispose of my box to-day nor on the FOLLOWING DAYS, for I can not end this letter without telling you how disagreeably surprised I have been once or twice, to hear, on arriving at the Opera, that my box had been sold, at the box-office, by your orders.†
Chpt 4 *

Definitions:

(1) (dispose as in: dispose of the waste)
to throw away
(2) (dispose as in: dispose of the matter)
to settle something so it no longer requires attention
(3) (dispose as in: dispose of the assets)
sell or transfer to another
(4) (dispose as in: disposed the troops along...)
the arrangement, positioning, or use of things
This sense of dispose can be used in the form disposal to indicate that a person can use something as they wish -- as in:
- I am at your disposal.
- She has many assets at her disposal.
(5) (dispose as in: Is she disposed to help?)
inclined (with a tendency to; or in the mood to)

This is usually seen in the form "disposed to..." or "disposed toward..."
(6) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Less commonly, disposing of can imply killing someone.