Hi Sujatha,
Try this....
TYPE-POOLS: VRM.
DATA: list TYPE vrm_values,
value LIKE LINE OF list.
PARAMETERS: p_list(20) AS LISTBOX VISIBLE LENGTH 20.
AT SELECTION-SCREEN OUTPUT.
DEFINE p_list.
value-key = &1.
value-text = &2.
APPEND value TO list.
CLEAR value.
END-OF-DEFINITION.
p_list: '1' 'Today',
'2' 'Key Date',
'3' 'Past',
'4' 'Other Period'.
CALL FUNCTION 'VRM_SET_VALUES'
EXPORTING
ID = 'P_LIST'
VALUES = list.
INITIALIZATION.
p_list = '4'.