We present in this paper lightning current measurements and LMA (Lightning Mapping Array) data associated with an upward bipolar flash observed at the Säntis Tower during the Summer of 2017. The polarity of the flash reversed during the negative initial continuous current phase by a positive pulse. The positive pulse was followed by two negative strokes. The positive pulse was presumably initiated in the lower positive region of the cloud where the positive end of a floating bidirectional leader connected to the lightning channel.