The phrase "were conditional upon" indicates that something is subject to certain terms or requirements. It can be replaced with synonyms such as "contingent on", "dependent on", or "subject to". Other possible options include "hinged on", "reliant upon", and "predicated upon". These synonyms all convey a sense of necessity or conditionality, emphasizing that the thing in question cannot be achieved or obtained without meeting specific criteria or following particular guidelines. Using synonyms for "were conditional upon" can help add clarity and precision to written or spoken communication, especially when discussing legal or business matters that involve complex contractual agreements or negotiations.