The phrase "was client" can be replaced with several synonyms depending on the context. For example, the phrase can be substituted with "was a customer," "was a user," or "was a patron." In a legal setting, "was a defendant" or "was a plaintiff" may also be appropriate. In a business context, "was a buyer" or "was a purchaser" may work, while in a service-oriented environment, "was a recipient" or "was a beneficiary" might be appropriate. The choice of synonym depends on the context and the industry in which the phrase is being used, but the options are endless.