114.8b An object that looks for a “[spell or ability] that targets [something]” checks the current state
of that spell or ability’s targets. If an object it targets is still in the zone it’s expected to be in or
a player it targets is still in the game, that target’s current information is used, even if it’s not
currently legal for that spell or ability. If an object it targets is no longer in the zone it’s
expected to be in or a player it targets is no longer in the game, that target is ignored; its last
known information is not used.
114.8c An object that looks for a “[spell or ability] that targets only [something]” checks the
number of different objects or players that became the target of that spell or ability when it was
put on the stack (as modified by effects that changed those targets), not the number of those
objects or players that are currently legal targets. If that number is one (even if the spell or
ability targets that object or player multiple times), the current state of that spell or ability’s
target is checked as described in rule 114.8b.
114.6a If an effect allows a player to “change the target(s)” of a spell or ability, each target can be
changed only to another legal target. If a target can’t be changed to another legal target, the
original target is unchanged, even if the original target is itself illegal by then. If all the targets
aren’t changed to other legal targets, none of them are changed.