If statements can be used for header/footer patterns to draw different values for different conditions (e.g., drawings require a different heading than all other documents). In these situations, creating a custom doc code/card field can provide additional functionality/flexibility for the header/footer patterns.
To begin, navigate to System Menu > Customization > Doc Code/Card Fields.
1. Create a custom doc code/card field by clicking the "+" icon in the top right of the grid.
2. Name the custom field, set the field type to "List," and create a new list.
3. Name the list, select the "Create own values" option, and create a "Yes" and a "No" value by typing them into the "Add new value" field and clicking the save button. Once both values are added, save the list. (Note: the "No" value is optional).
4. Once the list source is set to the new list, click save.
5. Navigate to the project and enable the new field to be used (Project Menu > Set Up > Project Configuration). From the "Fields & Equipment Types" tab, expand the "Doc Code/Card Fields" section and click on the arrows icon to enable the custom field (changes will auto-save).
6. Navigate to the code list (Project Menu > Cards > Code List) and set the values for the new custom field. Set the required code(s) to "Yes" and all other codes to "No." (Note: if the "No" value was not created, all other codes can be left blank (showing "- Select -"))
7. Navigate to the project header/footer settings (Project Menu > Set Up > Main > Headers and Footers) and set the header/footer pattern as required following this general formula: IF ("<CustomFieldName>"="Yes","<ValueIfYes>,"<ValueIfNo>").
Example:
All cards generated from drawing codes require the Item/Model number(s) in the header. If not a drawing, the PO number should be displayed in the header. The custom field name is "Alternative HF Pattern."
In this example, the formula would be set as follows: 
Once the values have been set, click "Save Project"