In Postman, you can change the base URL by following these steps:
1. Open Postman and navigate to the request you want to modify the base URL for.
2. In the sidebar, click on the `Params` tab.
3. In the `Params` tab, you will see a list of parameters. Look for a parameter named `base_url` or similar.
4. Modify the value of the `base_url` parameter to the desired URL for your request.
5. Click on the `Send` button to test the request with the new base URL.
Here's an example of how you could modify the base URL using the Postman API (JavaScript):