yes chamitojx you can contact your sponsor with the details(mail ID)on your Account summary page.look for his/her info such as email address in order to contact them for your request.
you can find it here .it will look like this in your Account summary page
and if any specific reason that you want to convey to your sponsor & if you can't find your sponsor's details you can contact the helpdesk and Submit a Ticket about it
just some tips ,not many only three tips's if you can make your sponsor believe that your worth upgrading
*tell him that your ready to work hard on tasks and surveys
*tell him that you can make some referrals for you or prove him by doing it so
*in other ways just tell him that you can do the above steps 100% and also need some help in upgrading
this would do .good luck