Pass, pass away, elapse, expire mean to move or come to a termination or end.
Pass and pass away imply gradual or gentle movement to another state or condition; they often imply a transition from life to death but they may suggest a transition from any one state or time or season to another.
Elapse suggests a movement that seems like the slipping and gliding away of something that moves silently or without notice; the word applies particularly to a period of time, either in reference only to itself or in reference to something that should have been accomplished within that time.
Expire basically means to breathe one's last breath and hence to die; but it comprehends the extended senses as well as the ordinary sense of die, and is used in reference to many things that come to an end as if by death.
It is often used with this underlying notion in reference to a period of time (as stated in a bond, a note, a promise, an agreement, a patent, or a lease) which has come to an end.