I'm using .NET notebooks for VSCode. Current version: v1.0.2419011

I'm trying to experiment with a nuget package

I first loaded the package like

#r "nuget: Microsoft.CodeAnalysis.Workspaces.MSBuild"

Then I realized I needed a preview version

#r "nuget: Microsoft.CodeAnalysis.Workspaces.MSBuild, 4.0.0-3.final"

However, the notebook won't let me change versions of the package. It errors with

Error: Microsoft.CodeAnalysis.Workspaces.MSBuild version 4.0.0-1.final cannot be added because version 3.11.0 was added previously.

I don't see any options for clearing the packages or forcing an overwrite. How do I change package versions after previously loading a different version?