Is there a way to change this parameter on a per agent basis?
No.
Or is there a way to display a notification in CAD when it happens?
Agent Workflows can be keyed off of state transtions; however, they cannot depend on the reason code. If you created a notification for the Not Ready state it would happen anytime they changed to that state.
If you have CCX Premium you could generate an email (Connect step, failed condition) in case the agents check their email more often.
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