The Collaborative International Dictionary of English v.0.48:

Emend \E*mend"\, v. t. [imp. & p. p. Emended; p. pr. & vb. n.
   Emending.] [L. emendare; e out + menda, mendum, fault,
   blemish: cf. F. ['e]mender. Cf. Amend, Mend.]
   To purge of faults; to make better; to correct; esp., to make
   corrections in (a literary work); to alter for the better by
   textual criticism, generally verbal.

   Syn: To amend; correct; improve; better; reform; rectify. See
        Amend.
        [1913 Webster]

WordNet (r) 3.0 (2006):

emend
    v 1: make improvements or corrections to; "the text was emended
         in the second edition"

Moby Thesaurus II by Grady Ward, 1.0:

72 Moby Thesaurus words for "emend":
   acculturate, advance, alter, ameliorate, amend, better,
   blue-pencil, boost, bring forward, civilize, compensate, correct,
   edify, edit, educate, elevate, emendate, enhance, enlighten,
   enrich, fatten, favor, forward, foster, give satisfaction,
   go straight, improve, improve upon, lard, lift, make all square,
   make an improvement, make good, make right, meliorate, mend,
   nurture, pay reparations, polish, promote, put right, put straight,
   put to rights, raise, recense, recompense, rectify, redact,
   redraft, redress, refine upon, reform, remedy, remunerate, requite,
   retouch, revamp, revise, rework, rewrite, right, set right,
   set straight, set to rights, set up, socialize, straighten out,
   transfigure, transform, upgrade, uplift, work over