Need to modify my question. I have tried other keywords and they will move up in levels, but it turns out that those that won't are because that keyword already exists at a higher level. So now how do I merge the two sets of photos so that they have same keyword at the right level?
Suppose you have two keywords, A > B > X and A > X, and you want to merge all the A > B > X pics to A > X and delete A > B > X. To do that:
1. In the Keyword List panel, hover the mouse over A > B > X and click the right-arrow that appears to the right of the keywodr. This will show exactly the pics that have A > B > X.
2. Select all those pics by doing Edit > Select All.
3. In the Keywording panel, in "Click here to add keywords", type "A > X". Now all the pics that had A > B > X will also have A > X.
4. In the Keyword List panel, right-click A > B > X and select Delete.
That worked! Thanks!
As one more step though I had to take after the last one was to go back to the original A>B>X folder and select them all, then take out the X keyword, because there were a bunch of other keywords too that should not have been deleted. I was afraid to delete them all as a group. If I had, would all the other photos have had their good keywords removed?
If I understand what you're asking: No, that extra step wasn't necessary. But it sounds like you've successfully merged the keywords, good.