Hello Vamsi
To confirm my understanding:
You have created a PlaceHolder Property in Capital Symbol to place the value of the Revision field on the diagram.
The contents of the Revision field is "Alpha,2631".
I believe that the entire contents of the field will be displayed, there is no way to parse the contents of the field.
The only workaround that comes to mind is to make the contents of the Revision field be "Alpha" and place the remaining "2631" into the Short Description field. Then you can control which one (or both) are displayed.
Regards,
Pat