I've been around a company that was 180+ years old (so rebranding was non-trivial ;)). They switched to an acronym based on the original name, so there was was 1) a direct link between old and new, 2) old branded tgat was mussed wasnt a big deal for bew customers, and 3) everyone called it by the acronym going forward.
A similar approach might work for you and allow an incremential phase out of the old brand over time. Instead of HxHxHx, it's now HITD (HxHxHx IT Desktop)
I once did a write up about Aflac's rebranding because I worked there for over five years and couldn't find a write up of it anywhere. I think that blog is no longer available to the public, so we may be back to "It doesn't exist anywhere online that I can tell."
A similar approach might work for you and allow an incremential phase out of the old brand over time. Instead of HxHxHx, it's now HITD (HxHxHx IT Desktop)