(a) A pharmacy benefits manager or its agent shall cancel and reverse a therapeutic interchange on written or verbal instructions from a prescriber, the beneficiary, or the beneficiary's representative.

(b) If a therapeutic interchange is reversed, the pharmacy benefits manager or its agent shall:

(c) If the therapeutic interchange occurred through a mail order pharmacy and a beneficiary will exhaust an existing supply of the originally prescribed prescription drug before a replacement shipment will arrive to the beneficiary, the pharmacy benefits manager or its agent shall arrange for dispensing of an appropriate quantity of replacement prescription drugs at a local community pharmacy at no additional cost to the beneficiary.

(d) A pharmacy benefits manager or its agent may not be required to cancel and reverse a therapeutic interchange if a beneficiary is unwilling to pay a higher copayment or coinsurance associated with the originally prescribed prescription drug.