was the second logical a replacement for the first (first: fld1 second: fld1, fld2, fld3) or was it an alternate lookup (first: fld1 second: fld2, fld3).
If an alternate, there is no need to make a change.
If a replacement, you could get rid of the first, or just recreate it with the composite key instead of adding the second logical.
You do not need to use all of the keys in a logical, as long as you are using the first x keys (if logical fas keys of fld1, fld2, fld3 you can also use that logical to search by just fld1 or just fld1, fld2 -- you cannot search just by fld2 or just fld3 or just fld2, fld3)
Are you still waiting for an answer on this or is your question resolved.