How do I remove a package from my project?,How do you delete an unwanted package from your project?

I imported the Post Processing Stack from the asset store and received this error: error CS0104: 'MinAttribute' is an ambiguous reference between 'UnityEngine.PostProcessing.MinAttribute' and 'UnityEngine.MinAttribute' The only way I've found to fix it is to get the stack from the package manager. But how do I remove the older package from my project? ,I imported the wrong version of the Post Processing stack and now need to get the correct one, how do I delete the **Package** from the project? I also received this error when I imported the Post Processing Stack from the asset store: error CS0104: 'MinAttribute' is an ambiguous reference between 'UnityEngine.PostProcessing.MinAttribute' and 'UnityEngine.MinAttribute'