Two Azure web apps using same Azure SQL Server, two databases

I have prod version of an Azure web app running. I need to create a UAT version. I want to use the same Azure SQL Server but a different database.

When I go to create the new Web App:

• I use the existing Subscription and Resource group.
• I give it a new instance name Publish with code
• Runtime stack is .NET 6 (LTS)
• Region is the same as prod

When I go to Database tab I get a warning “Creating a database requires a new App service plan.” so I can’t seem to relate the new instance.

I’ve been testing with the 2nd instance in VS 2022 so there’s no problem with it. But I need a published version so that users can test it.

Can this be done, or have I missed something?