1. I didn't beat her
- The passive voice of the given sentence would be: She was not beaten by me.

2. She has learned her lessons
- The passive voice of the given sentence would be: Her lessons have been learned by her.

Explanation:
When changing a sentence from active voice to passive voice, the object of the active sentence becomes the subject of the passive sentence. In this case, "her" becomes the subject in the passive voice. The verb in the active voice becomes the main verb in the passive voice, and the subject in the active voice becomes the object in the passive voice.
In the first sentence, "I didn't beat her," the active voice is used to express the action of not beating someone. When changed to passive voice, the focus shifts from the doer of the action (I) to the receiver of the action (her).
In the second sentence, "She has learned her lessons," the active voice indicates that she is the one who has learned the lessons. When converted to passive voice, the emphasis is on the lessons being learned by her rather than her being the one learning them.
Overall, understanding how to change sentences from active voice to passive voice is essential for effective communication and writing in various contexts.