Your partner already owns the Vitalmonitor FLOW HRV and you want to use the sensor as well? Then there is now a so-called Partner ID for you.
With this ID you can also use the APP independently. We recommend to use a separate tablet or smartphone for each person who wants to measure. It is possible to measure 2 or more people on the same device, but they always have to log in and out when the other person wants to measure.