General Synonyms:
* Diminished
* Reduced
* Lessened
* Decreased
* Subsided
* Eased
* Waned
* Recessed
More Specific Synonyms:
* Moderate (for intensity)
* Relent (for severity)
* Subside (for storms or pain)
* Ease (for pressure or tension)
Example Sentences:
* The storm abated (diminished) in the afternoon.
* The pain abated (subsided) after taking the medication.
* His anger abated (eased) after talking to his friend.
The best synonym to use will depend on the specific meaning of "abated" in your sentence.