'Work over' suggests the process may require a significant amount of time to improve.

Time Intensive

The phrase is often used with the expectation that the effort will lead to a better result.

Positive Outcome

'Work over' can mean making several changes, not just one.

When questioning, 'work over' means the person was subjected to heavy, relentless questioning.

In an interrogation context, 'work over' can suggest the use of pressure or intimidation.

'Work over' implies examining something in great detail to understand it completely.

'Work over' can indicate persistence in studying until the subject is mastered.