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, enable the field setting for "Header/Footer Pattern" and click save when complete.
5. Navigate to the project and enable the new field to be used (Project Menu > Set Up > Project Template). In the "Doc Code/Card Fields" section, 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"