Action for a takeover OPEN

An application program that is enabled for persistence enters its TPEND exit routine under the following conditions:

For single-node persistent sessions, an alternate application program that is capable of persistence issues OPEN ACB to takeover the sessions from the original application.
For multinode persistent sessions, an application program with the same network name has enabled persistence on another VTAM® when this VTAM connects to the multinode persistent sessions coupling facility structure. Specifically, this occurs when a persistence-enabled application program is open and VTAM is not connected to the coupling facility. Later, when VTAM connects to the coupling facility, it detects an open application program with the same name that is already enabled for persistence.
For multinode persistent sessions, an additional reason for the TPEND exit to be driven is the receipt of a forced takeover request from another node in the sysplex. Specifically, a copy of this same application has issued OPEN ACB on another node, and has specified FORCETKO=YES on the ACB macroinstruction. This setting indicates that the new copy of the application has reason to acquire ownership of the existing sessions, so this image of the application must be cleaned up before the new image can successfully acquire the sessions.
Tip: An application can prevent this final form of TPEND exit usage by specifying PARMS=(FORCETKO=NONE) or PARMS=(FORCETKO=SINGLE) on its SETLOGON OPTCD=PERSIST macroinstruction.

In all cases, VTAM closes the application program by scheduling the TPEND exit routine with reason code 12.

For all TPEND conditions, VTAM does not allow the application program to respond to any operator commands, nor does it allow the application program to establish any new sessions. The original application program must issue CLOSE. Any RPL macroinstructions issued by the original application program will fail. Any pending or future communication request is marked with (RTNCD,FDB2)=(X'10',X'0D') to indicate that VTAM is inactive for that ACB. VTAM places any sessions in the recovery pending state and holds the allocated resources for future availability during session recovery.