An important challenge in service robotics is to design user interfaces and interaction capabilities that can be used intuitively to enable the potential users to benefit from the robot's functionalities and to allow effective collaborative task execution. The Interactive Behavior Operated shopping Trolley (InBOT) addresses this issue at the example of supporting complex shopping tasks in large supermarkets. The actual control of the robot is shared or traded between the robot and it's dedicated user ranging from closely coupled haptic-based interaction via observation-based interaction up to loosely coupled command-based interaction. The four modes of operation of InBOT, i.e. the manual steering, following, guiding and autonomous mode, the transitions between them and the relevant modalities of interaction are introduced. Finally the paper is completed by describing the results of user studies.