Antonyms for "settles upon" can vary depending on the context in which it is used. In the case of decision-making, antonyms can include "changes," "reverses," or "revokes." Regarding physical actions, the opposite of settling upon can be "disturbing," "dislodging," or "unsettling." In terms of mental states, antonyms can be "uncertain," "undecided," or "doubtful." If the phrase pertains to the final location of an object, antonyms can include "remove," "displace," or "relocate." Therefore, understanding the context of "settling upon" is crucial to determining the appropriate antonyms to be used.