If scientists have determined the Neanderthal genome, we will be able to create a neanderthal person. A human embryo is probably close enough genetically to provide the vehicle. We just need to synthesize the DNA, remove the Homo sapiens DNA and replace it with Neanderthal DNA, let nature take its course and, voila, a Neanderthal.
Of course, there are ethical considerations, but we could we could perform the operation in China and finance it with a crowdfunded ICO. We'll call it NeanderCoin;)
don't want upgrade the species now do we.