General Synonyms:
* Reproduction
* Reconstruction
* Replication
* Re-creation
* Simulation
* Performance (especially for historical or theatrical reenactments)
* Reconstitution
* Living history (for historical reenactments)
* Reliving
* Replaying
More Specific Synonyms:
* Historical reenactment (for reenactments of historical events)
* Battle reenactment (for reenactments of battles)
* Costume drama (for theatrical reenactments)
The best synonym to use will depend on the specific context of the sentence.