The Admin on your account has the authority to assign who has the authority to make Application purchases on behalf of the company. You will have to notify your admin to update your account.
For Admins, you have the option to go to <Manage System Settings<Manage User Accounts. Here you can assign new users and assign designations. To allow a user to make purchases on behalf of the organization, locate the user and under ACTION, locate the "Edit Permission" icon. Here you can assign users to allow them to make purchases.