To put into a new and improved form or condition; to restore to a former good state, or bring from bad to good; to change from worse to better
1909, H. G. Wells, The History of Mr. Polly Chapter 9
To return to a good state; to amend or correct one's own character or habits
It is hoped that many criminals, upon being freed, will eventually reform.
To form again or in a new configuration.
The regiment reformed after surviving the first attack.
Reformation
A catalytic process, whereby short-chain molecules are combined to make larger ones; used in the petrochemical industry.