Disabling parameter in Concurrent Program based on the above parameter.

Disabling parameter based on the above parameter:
Para1
organization: PER_ORG_UNITS_RESTRICTED_BY_DATE_PARAM
P_ORGANIZATION_ID

Para2:
dummay org: PER_CHAR
 P_DUMMY_ORGANIZATION
SQL Statement
select decode(:$FLEX$.PER_ORG_UNITS_RESTRICTED_BY_DATE_PARAM:NULL,'','X','') from sys.dual

para3:
Empolyee: PER_EMPLOYEES_SKIP
P_PERSON_ID

Check for details "Absence Report" seeded report for the same in HRMS.