I will be installing a floating hardwood for my first time and I need a suggestion. Right now half the floor is covered in carpet and the other half is covered in Vinyl tile about 3/32 thick. I will be removing the carpet but prefer not to tackle removing the vinyl. Can I lay the moisture barrier then lay the floor with this change in floor height? Or do I have to either remove the vinyl tile (which I really don't want to) or build up the other area to match the height of the tile? And if I do have to build it up to match the height what is the best and easiest way to do that?
I hope I explained this clearly.
Thanks for your advice in advance.

If your on concrete you can simply feather out that area with patch. If your on a wood sub-floor you can feather it out with layers of roofing felt. Read your manufacturers installation guidelines for floor flatness.

Thanks ! any recomendations of the proper product for the patch?

I like Mapei Planipatch, mixed with their latex additive. There's also a number of cement based,( some already latex modified ), patching compounds on the market....Ardex, Durock, Vitex, etc.

Make sure the slab is clean. Also doesn't hurt to prime the slab with liquid latex before patching.

Thanks again! Love these kind of forums for advice.
It's a concrete slab so is there a problem with using felt paper to level it?

Manufacturers typically suggest a cement based patching compound over concrete.