I'm attempting to describe the process of changing the sign of a variable (in a math/programming context), but I'm not able to come up with a singular word for that process, even though it seems like there should be one. I presume I could use "negate," but that already has meanings in regards to logic, where you can turn an argument p into not p, and in regular English, where it means "to nullify" and "to cause negative results" - both of which, though particularly the first definition, are not completely accurate in regards to the actual process.
Succinctly, is there a single word (as opposed to a phrase) that means "to change the sign of"?