ASP.NET Core 2 MVC manipulating return url

You could not control the web browser url directly from server side.

For a workaround, you could try to URL Rewriting Middleware in ASP.NET Core like

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {            
        services.AddSession();
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {

        app.UseSession();
        var options = new RewriteOptions()
       .Add(context => {
           var request = context.HttpContext.Request;
           var query = request.Query;
           StringValues color = "";
           if (request.Path.StartsWithSegments("/Home/Test", StringComparison.OrdinalIgnoreCase)
           && query.TryGetValue("color", out color))
           {
               var response = context.HttpContext.Response;
               response.StatusCode = StatusCodes.Status301MovedPermanently;
               context.Result = RuleResult.EndResponse;
               context.HttpContext.Session.SetString("query", request.QueryString.Value);

               var items = query.SelectMany(x => x.Value, (col, value) => new KeyValuePair<string, string>(col.Key, value)).ToList();
               // At this point you can remove items if you want
               items.RemoveAll(x => x.Key == "color"); // Remove all values for key
               var qb = new QueryBuilder(items);
               response.Headers[HeaderNames.Location] =
                   request.Path + qb;
           } 
           else if (request.Path.StartsWithSegments("/Home/Test", StringComparison.OrdinalIgnoreCase)
           && !query.TryGetValue("color", out color))
           {
               context.Result = RuleResult.SkipRemainingRules;
               request.QueryString = new QueryString(context.HttpContext.Session.GetString("query"));
           }
       });

        app.UseRewriter(options);            

        app.UseMvc(routes =>
        {
            routes.MapRoute(
                name: "default",
                template: "{controller=Home}/{action=Index}/{id?}");
        });
    }
}