Antonyms for the phrase "call in to question" include "affirm," "acknowledge," and "validate." When we affirm something, we are expressing our complete support and belief in its veracity. Acknowledging something means to accept it without questioning or challenging its validity. Validating something means to confirm or prove its legitimacy. In contrast, to call something into question is to doubt or challenge its truthfulness or validity. Therefore, using antonyms for "call in to question" can help convey confidence, support, and validation in a statement or argument.