> ## Documentation Index > Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt > Use this file to discover all available pages before exploring further. # Document parameter changed > Format document properties with the Document parameter changed event, fired before a comment, registration parameter, ExternalID, or priority changes. ## What it does The handler of this event can be used for formatting some of document properties. ## Document properties * Comment * Value of the registration parameter * ExternalID * Document priority (specified in form of a string). For the list of admissible values, see the description of the [TProcessingPriority](/flexi-capture/appendix/scripts/tprocessingpriority-appendix-scripts) object. ## When it is launched The script is launched prior to changing a document property. ## Parameters | **Name** | **Type** | **Access** | **Description** | | -------------------- | -------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------ | | Document | [IDocument](/flexi-capture/appendix/scripts/idocument) | Internal[\*](/flexi-capture/appendix/scripts/documentparam-change#asterisk) fields of batch documents and pages are unavailable | The document | | PropertyModification | [IPropertyModificationInfo](/flexi-capture/appendix/scripts/ipropertymodificationinfo) | Read/write | Stores information on the property being changed | \* - The internal field requires loading the object into memory.