49.2.

# ipa user-remove-principal <user> <useralias>
--------------------------------
Removed aliases from user "user"
--------------------------------
  User login: user
  Principal alias: user@IDM.EXAMPLE.COM

# ipa user-show <user>
  User login: user
  ...
  Principal name: user@IDM.EXAMPLE.COM
  ...

# ipa user-remove-principal user user
ipa: ERROR: invalid 'krbprincipalname': at least one value equal to the canonical principal name must be present