Hi,
Try below code.
REPORT Test.
TABLES SSCRFIELDS. "Fields on selection screens
type-pools : icon.
SELECTION-SCREEN FUNCTION KEY 1. "button on the application toolbar
PARAMETERS P_DAT LIKE SY-DATUM.
INITIALIZATION.
"Populating button text
MOVE 'Execute' TO SSCRFIELDS-FUNCTXT_01.
AT SELECTION-SCREEN.
IF SSCRFIELDS-UCOMM = 'FC01'.
ENDIF.
START-OF-SELECTION.
END-OF-SELECTION.
Regards,
Murthy