The same email address or mobile phone number cannot be used for more than one role. However, in the rare instances where an authorised user wishes to play more than one role (for example a Doctor who is also coordinating trips, or a clinic manager who is also coordinating trips), that user could set themselves up using a different email in the second role. However, login details should not be shared between users, to maintain data protection and to avoid actions during trips being attributed to the wrong person.