Hi,
IPCC Express marks the agent as reserved, when it selects the agent to deliver a call. On the select step, once the agent is selected, he is put into the reserved state and IPCC looks for any other steps you might have configured after selecting the agent after finishing those steps, the agent selected ( or marked as reserved ) gets the call.
I guess this state shouldnt be there for a long time and most of the times we dont see it at all.
HTH