Verb (5-dan, る, intransitive)
1. to change places (with); to be replaced (with, by); to be changed
人は入れ替わっても、何も変わらない。Even if people are replaced, nothing changes.
Verb (5-dan, る, transitive)
2. to change (seats, shifts, etc.; with someone); to switch; to exchange
お前たち、今入れ替わったよな?You two just switched places, didn't you?