616.1. If two or more replacement and/or prevention effects are attempting to modify the way an event affects an object or player, the affected object's controller (or its owner if it has no controller) or the affected player chooses one to apply, following the steps listed below. If two or more players have to make these choices at the same time, choices are made in APNAP order (see rule 101.4).616.1b If any of the replacement and/or prevention effects would modify under whose control an object would enter the battlefield, one of them must be chosen. If not, proceed to rule 616.1c.

616.1c Any of the applicable replacement and/or prevention effects may be chosen.

616.1d Once the chosen effect has been applied, this process is repeated (taking into account only replacement or prevention effects that would now be applicable) until there are no more left to apply.
Example: Two permanents are on the battlefield. One is an enchantment that reads "If a card would be put into a graveyard from anywhere, instead exile it," and the other is a creature that reads "If [this creature] would be put into a graveyard from the battlefield, instead shuffle it into its owner's library." The controller of the creature that would be destroyed decides which replacement to apply first; the other does nothing.

616.2. A replacement or prevention effect can become applicable to an event as the result of another replacement or prevention effect that modifies the event.
Example: One effect reads "If you would gain life, draw that many cards instead," and another reads "If you would draw a card, return a card from your graveyard to your hand instead." Both effects combine (regardless of the order they came into existence): Instead of gaining 1 life, the player puts a card from his or her graveyard into his or her hand.