I have a stored procedure that takes 2 DATETIME parameters. The parameters can be NULL whereby I set the parameters to specific values in the stored procedure but if they are populated from the SSRS report then I use those values. In SSRS I have a problem where I am needing to change the NULL label to something else but I can't find a way to do that. In the REPORT PARAMETER PROPERTIES I set each parameter to a DATE/TIME value with the ALLOW NULL VALUE checkbox checked and visible so that the user can uncheck the NULL checkbox and set the actual date parameters using the calendar button. 

Is there a way to change the NULL label for the checkbox? Any help or direction would be appreciated. 

Here is the PIC of the PREVIEW SCREEN for the report in SSRS:

[![enter image description here](https://i.stack.imgur.com/Q8lCb.png)](https://i.stack.imgur.com/Q8lCb.png)