"Six half a dozen of the other" is a phrase used to describe a situation where two options are essentially equivalent or have the same outcome. However, there are a number of synonyms that can be used in place of this phrase depending on context and tone. Other similar idiomatic expressions include "much of a muchness," "tomato, tomahto," "six of one, half a dozen of the other," or "no difference at all." Alternatively, one could simply say that the two options are indistinguishable, equivalent, or interchangeable. Ultimately, the goal of using a synonym for "six half a dozen of the other" is to convey a sense of indifference or lack of preference between two choices.