To edit or delete a user connected to your account you’ll need to be either the Admin or owner of the account;
In the lefthand side menu, select 'Setup' and then 'Team'.
You’ll see each user’s role and status next to their name.
Click the edit icon to select a new role for a user, from Admin, Standard user, Sampler and View Only, or click the Delete icon to remove user access.
Read more about different user roles and access here.