How do I hide previous responses in an email?

You can enable the activity stream to display only the most recent employee response to agents. This optimizes the agent’s workload because in the activity stream each message is only shown once.

All you need to do it enable a profile option. The profile option isn't enabled by default, so here's how you enable it:

1. In Setup and Maintenance, click and search and select Manage Administrator Profile Values.
2. Enter ORA_SVC_PREVIOUS_RESPONSE_EMAIL_REMOVAL_ENABLED in the Profile Option Code field.
3. Set the Site value to Yes, then save your changes.