"Be conditional upon" is a phrase that indicates that something is dependent or contingent on another thing. There are several synonyms for this phrase, including "contingent on," "subject to," "hinged on," "conditional on," "reliant on," and "dependent on." These synonyms carry the same meaning as "be conditional upon" and can be used interchangeably depending on the context. For instance, if you want to express that a job offer is dependent on someone passing a drug test, you can use any of these synonyms such as "the job offer is contingent on passing a drug test," "the job offer is subject to passing a drug test," or "the job offer is conditional on passing a drug test".