![UML use case extend relationship is used to show how and when some optional extending use case can be inserted into extended (base) use case. UML use case extend relationship is used to show how and when some optional extending use case can be inserted into extended (base) use case.](https://www.uml-diagrams.org/use-case-diagrams/use-case-extend-condition.png)
UML use case extend relationship is used to show how and when some optional extending use case can be inserted into extended (base) use case.
![Use case diagram that presents several use cases offered to the media... | Download Scientific Diagram Use case diagram that presents several use cases offered to the media... | Download Scientific Diagram](https://www.researchgate.net/publication/252783784/figure/fig3/AS:667858543591425@1536241293242/Use-case-diagram-that-presents-several-use-cases-offered-to-the-media-consumer-The-send.png)
Use case diagram that presents several use cases offered to the media... | Download Scientific Diagram
![UML use case extend relationship is used to show how and when some optional extending use case can be inserted into extended (base) use case. UML use case extend relationship is used to show how and when some optional extending use case can be inserted into extended (base) use case.](https://www.uml-diagrams.org/use-case-diagrams/use-case-extension-points.png)
UML use case extend relationship is used to show how and when some optional extending use case can be inserted into extended (base) use case.
![Modeling optional behavior with UML extension points and extend relationships - Support - Bizzdesign Support Modeling optional behavior with UML extension points and extend relationships - Support - Bizzdesign Support](https://support.bizzdesign.com/download/attachments/39814459/worddavc3662270d3b0ad8f190b97b5d9b0619b.png?version=1&modificationDate=1559903155576&api=v2)