If one feels the favoured candidate is certain to be elected in any case, insincerely ranking the second candidate first guarantees them a full vote if needed.
Retractions share with original statements the attribute that they are in some cases made insincerely, in some cases for personal gain, and in others under duress.
Tactical voting is where voters do not vote in accordance with their true preferences, but instead vote insincerely in an attempt to influence the result.