Interactive Call Distribution (ICD) agents can not park their second customer after they park their first customer. They cannot park, transfer or hold the call. When they press the More button, no softkey options for these features show up.
This problem is observed because the line runs out of virtual lines. A line can have only two virtual lines active at the same time. When a call is on hold or parked, another line is required to transfer or park subsequent calls. Since the line is occupied by the first call, the transfer and park options will not show up.
To avoid this situation, have another internal normal Dialed Number (DN) assigned to one of the lines of the agent's IP phone. Have the agent perform the following steps:
Enter the number of your internal line, not the ICD line.
Press Transfer again before it connects.
Answer the ringing line. Press the Line button or answer.
Note: Call Park is supported only in CRS 3.x. If Call Park is attempted in some of the Customer Response Applications (CRA) 2.x versions, it may leave the agents in Stuck In-Session state. For more information, refer to Cisco bug ID CSCdu41417.