AjaxControllerA.cs

public class AjaxController : Controller
{
    readonly IDatabase _db;

    public AjaxController(IDatabase db)
    {
        _db = db;
    }
    
    // ... snip ...

    [HttpGet]
    public PartialViewResult GetLedgerEditRow(int id)
    {
        var ledger = _db.Query(new GetLedgerByIdQuery(id));
        return PartialView(ledger);
    }
}

AjaxControllerB.cs

public class AjaxController : Controller
{
    readonly IDatabase _db;

    public AjaxController(IDatabase db)
    {
        _db = db;
    }
    
    // ... snip ...

    [HttpPost]
    public ActionResult CreateLedger(LedgerEntity ledger)
    {
        if (ModelState.IsValid)
        {
            _db.Execute(new CreateLedgerCommand(ledger));
            return new HttpStatusCodeResult(HttpStatusCode.Created, "it worked");
        }
        return new HttpStatusCodeResult(HttpStatusCode.InternalServerError, "Errors");
    }
}