A 52-year-old woman with chronic schizophrenia managed on haloperidol 10 mg daily for 15 years presents with involuntary repetitive tongue protrusions, lip smacking, and choreiform movements of the fingers bilaterally that have developed gradually over the past six months. Her AIMS score is 14. Her psychotic symptoms have been well-controlled on this regimen, with a PANSS total score of 52. She has no history of exposure to other dopamine-blocking agents. She has previously failed adequate trials of olanzapine and quetiapine due to intolerable metabolic side effects before being stabilized on haloperidol. The PMHNP is developing a treatment plan to address the tardive dyskinesia while maintaining psychiatric stability. Which of the following is the most appropriate approach?