In this paper, we discuss about interface for personal robot systems that are not supported by social authority. The paper consists of two parts. The first part describes HuRIS, a human-robot interactive system for supporting human-robot and human-human communication. HuRIS aims to be active as an agent of a user. A robot of HuRIS can accept voice commands by its voice recognizer, and can reply via its simple natural language processing system and voice synthesizer. The robot of HuRIS has the ability of asking a human for help by using the voice synthesizer when it is trapped in some failure. However, we see that humans around our robot do not always accept its commissions. The necessary condition that a human accepts a request of a robot is not known. So, the second part of our paper describes experiments on robot's commission in some detail. In Experiment 1, we show that a request of a robot supported by no social authority is not accepted by a human. In Experiment 2, we show by using HuRIS's interface that the performance of the subjects is generally similar for human and robot commissions. The paper concludes that the interface for HuRIS as a personal mobile robot system is effective.