My assistant and I are using two Lightrooms (i.e. two serial numbers) and need to share between our two computers. I provide originals to her onto a flash drive. She tags them and returns them to me. I then copy the photos from her flash drive onto my computer and load them in my LR. The photos appear but witthout any editing or tagging. We need to be able to have her working on the photos on her computer with her copy of LR and me on my computer with my version of LR being able to access what is already tagged and given back to me. This seems hard. We need advice on if it is at all possible to have two computers simultaneously working on LR . I bought her her own version because I was told at the time of purchasing that that was the only way to share. Please advise urgently! Thanks.
Sounds like your assistant isn't instructing Lightroom to write the tagging and editing to the files themselves, so wehn the files return to you, they don't have editing and tagging information. She need to select the photos in Lightroom and then Ctrl-S (Cmd-S on Mac). Or alternatively turn on the option to autmoatically write this information to the files.
If you are using RAW photos, then this information will be written to a sidecar XMP file, and your assistant must provide you with the sidecar file. If these photos are not RAW photos, then the information is written directly into the photo file itself.
Lightroom wasn't designed to be a multi-user program, and so it is truly not possible to have two people working on the same catalog at once. The way you are doing things, as modified above, is probably the way to go.
As an alternative, you can transfer (portions of) catalogs as well as photos back and forth and then all of these issues disappear, but a catalog might be rather large for a flash drive (or maybe not, it depends)