To change into a new or better form
reorganize, reconstruct, rearrange, transform, ameliorate, redeem, rectify, better, rehabilitate, improve, correct, cure, remedy, convert, mend, emend, amend, restore, remodel, revise, repair, rebuild, reclaim, revolutionize, regenerate, refashion, renovate, renew, rework, reconstitute, make over, remake; see also change 1.
Antonyms degrade, corrupt*, botch.
To correct evils
amend, clean out, give a new basis, abolish, repeal, uplift, ameliorate, rectify, regenerate, redeem, rehabilitate, give new life to, remedy, stamp out, make better, standardize, bring up to code, set straight; see also sense 1; improve 1.
To change one's conduct for the better
resolve, mend, mend one's ways, regenerate, make amends, have a new conscience, make a new start, make resolutions, turn over a new leaf, see the error of one's ways, change one's ways, straighten out, go straight*, clean up one's act*, shape up*, get religion*, put on the new man*, swear off*; see also sense 2.