Add Then  and Else statements 
 - Choose Tools, Global Change.
- Click New, or select an existing specification and click Modify.
- Click in the Then section to define a Then statement and in the Else section to define an Else statement. 
- Click Add.
- In the Parameter field, select a data item.
- In the Parameter/Value field, select a data item to use as the first parameter in the statement. Select Custom to type a text or numeric value.
- Select an operator to define an arithmetic equation to change numeric data.
 
 Arithmetic operators can connect two data items, a data item and a number, or two numbers.
 
- Depending on the data items selected for the first parameter, either type a value in the second Parameter/Value field, or select it from a predefined list.
 
 If the first parameter requires a valued definition rather than a second parameter, you can leave this field empty.
Note
 - You can define Then statements without defining either an If statement or an Else statement. To define an Else statement, you must first define an If statement.