Once you change the properties for a particular CICS® region, you should upload the new properties to the CICS BAC application on the mainframe host. Follow these steps
Procedure
If you are not currently in the Region Properties window,
select the desired region folder in the CICS BAC
main window and then double-click the Region Properties object in
the view pane.
Click the Upload icon on the toolbar or select File > Upload Properties to Host.
This opens a dialog box that lets you view the object
and region being uploaded.
Click OK to start the upload.
CICS BAC connects to the mainframe and uploads
the properties. If you haven't already set up the host user ID and
password, you will be asked to enter your user ID and password to
complete the operation.