How to dynamically add virtual terminals without recycling TPX.
TPX® Session Management for z/OS
If you run out of Virtual Terminals you can use the VTADD command to add more to TPX without recycling TPX.
To add virtual terminals dynamically:
Note: The member name must only contain the new virtual terminal or printer names.
Remember to add these to the primary VTAM ACB member so that at the next TPX start they are included eliminating the need to run VTADD.