With the increasing number of IoT devices deployed, the problem of switching ownership of devices is becoming more apparent. Especially, there is a need for transfer protocols not only addressing a single unit ownership transfer but secure transfer of a complete infrastructure of IoT units including also resource constraint devices. In this paper we present our novel ownership transfer protocol for an infrastructure of IoT devices. The protocol is light-weight as it only uses symmetric key operations on the IoT side. The ownership transfer protocol is carefully security evaluated both using a theoretical analysis and with automatic protocol verification. In addition, we show the feasibility of the ownership transfer protocol through a proof of concept implementation including performance figures