Yes, as Romantique says you’ll need to contact support (sorry I missed the Halion 3 issue in my first reply).
BUT if you don’t get a reply pretty quickly you might want to consider whether it’s worth waiting as the 50% sale offer is only valid until 19th Feb and after that even if there is an upgrade route it’s likely to be more than the current full price with discount.
(Here in the UK the standard upgrade from Halion 4 is £171 and the current discounted price on a non-upgrade license is £150).
Good luck.