---
title: Prescribing System-Initiated Change Process for LTPAC – Requirements/Best Practices (R.312)
slug: eprescribing/guide/prescribing-system-initiated-change-process-for-ltpac-requirementsbest-practices-r312
docTags: 
createdAt: 2026-07-09T20:15:13.846Z
---

# Overview

This section holds the application certification requirements located in the [Prescribing System-Initiated Change Process for LTPAC - Requirements/Best Practices](docId\:dzEQxDB2pjQCdzSsiEb7t) section in the guide.

## R.312

**R.312:** In LTPAC prescribing systems, when making a prescription change using a CancelRx followed by a NewRx, a MessageRequestCode shall be used to identify the type/severity of change made. This field shall be sent in both the CancelRx and the subsequent NewRx.