The phrase "is conditional upon" denotes a dependency or reliance on something else. It implies that if one condition is not met, then the outcome will be affected. There are several synonyms for this phrase, including "depends on," "relies on," "hinges on," "is contingent on," "requires," and "is subject to." Each one of these synonyms highlights the notion that there is a significant factor or condition that must be met or fulfilled for the desired outcome to be realized. These synonyms can be used interchangeably in various contexts and can elevate the language used in formal communication.