A latching mechanism for selectively disengaging an upper pump from a motor in an ESP. The latching mechanism comprises barbs formed on an upper end of an upper shaft that are engaged by a tool to lift the upper shaft until a lower end of the upper shaft disengages from an upper end of a motor shaft. When the upper pump is disengaged from the motor shaft, only a lower pump is driven by the motor and flow of well fluid is circulated past the disengaged upper pump via a bypass line. The upper pump shaft may reengage the motor shaft if additional lift is required.