When the substance of a thought remains but its wording changes, the case is no longer a strict verbal reproduction. The source discusses this degree under ighārah and maskh.
One writer may replace words with synonyms, omit part of a line or rearrange its elements. These moves alone do not guarantee an improved poem.
Three questions matter:
1. Is the earlier thought still intact?
2. Are changes merely superficial?
3. Does the new form improve clarity, concision or rhetorical force?