Information services are designated for information processing intensive tasks and may require different levels of human involvement in their execution, e.g., in information processing and analysis. The handling of variability in information service systems incorporates the concern of human involvement in service execution or, as we denote it, functioning mode of service. The existence of different functioning modes of services raises a problem of multi-mode service composition. In the paper we propose the use and the extension of variability representation model to represent variability in the information service system and present the multi-mode service composition approach to derive consistent flows of both abstract and concrete services.