Reserve agents are available on the reserve channel in exceptional circumstances, such as a configured threshold is breached. If channels are within the configured thresholds, reserve agents are unavailable.

The system does not have any default service thresholds. If you want to configure reserve agents and channel prioritisation based on channel overload, you must configure service thresholds. You must set a service threshold for each channel at a minimum. The base channel threshold can be overridden by more specific services. For example, attributeSet=Channel.Voice,Language.English.