"Go one's reward" is an idiomatic expression used when someone dies. It's a polite way of referring to death or passing away. However, there are many other synonyms that can also be used to express the same meaning. Some common synonyms for "go one's reward" include "pass away," "expire," "depart," "go to heaven," "meet one's maker," "cross over," "kick the bucket," "bite the dust," "shuffle off this mortal coil," "meet one's end," and "give up the ghost." All of these expressions mean the same thing, but the choice of words ultimately depends on context, tone, and personal preference.