SOS feature

[Amele]

So I enabled the SOS feature and it says you should put down one or two contacts for emergencies and I put down my son-in-law and then tried to put down my daughter, and it won't let me add her. So I deleted him as the contact and tried to add her (he works a city away and she is usually around) and it won't let me add her. I can add him back but
it refuses to let me substitute her or even add her. Anybody?