Jill, "change the name and LNAB if needed" does mean that it is OK to create an entirely new profile with a new first and LNAB.
If you look at the guidelines the only restriction on adopting a Profile with "Unknown" LNAB, is that you need to select one with the same gender. If there is a profile with the same 1st name it would be great to use it but it is not a requirement.
https://www.wikitree.com/wiki/Category:Recycle_Unknowns
If a profile on the recycle list already have a valid LNAB it should not be changed but all other data can be changed as required.
In a nutshell this is the guidelines:
1. If the LNAB is Unknown
a. Adopt a profile with the SAME gender
b. Remove the Category: Recycle Unknowns
c. Change the Name and LNAB if needed, and add all the other information, including your sources
2. If the LNAB is for example Smith, Jones, etc
a. Adopt a profile with the exact same LNAB
b. Remove the Category: Recycle Unknowns
c. DO NOT Change the LNAB. It should be used for the same LNAB, to keep the changes log consistent.
d. Add all other information, including your sources