cannibalize

Short definition from Wiktionary

Verb

1. 1
   To eat (parts of) another of one's own species.
2. 2
   To remove parts of (a machine, etc) for use in other similar machines.
3. 3
   To reduce sales or market share (for one of one's own products) by introducing another.
4. 4
   Rework old material; rehash.