ASP.Net Core Api middleware to end request by calling a controller action

Server : ASP.net Core Web API

Client : WinForms app using Refit and sending its version with each request (as a header)

How does the server check the client requests version, if it is wrong then reply by calling a controller action VersionError?

This code does not end the request:

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseRouting();
    app.UseAuthorization();

    app.Use(async (context, next) =>
    {
        foreach (var header in context.Request.Headers)
        {
            Console.WriteLine($"{context.Request.Path} : {header.Key}={header.Value}");

            if (header.Key == "CLIENT-VERSION" && header.Value != "5")
            {
                context.Request.Method = "GET";
                context.Request.Path = "/api/Error/VersionError";
            }
        }

        await next();
    });

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllers();
    });
}

[ApiController]
[Route("api/[controller]/[action]")]
public class ErrorController : ControllerBase
{
    [HttpGet]
    public Message<string> VersionError()
    {
        var reply = new Message<string>(errorMessage: "version error");
        return reply;
    }
}