How to do server-side date conversion and styling before sending it to jQuery datatable?

I use jQuery datatable in my project. The code for getting all data from database is:

var pm = _pmRepository.GetAllPMs().Reverse().ToList();

The repository pattern used for this purpose is:

 public IEnumerable<PM> GetAllPMs()
    {
        return context.PMs;
    }

My database has some columns with DateTime format. I want to convert date format. I have written a class that can do this:

public class DateTimeConverter
{
    PersianCalendar pc = new PersianCalendar();
public string DateConverter(string inputDate)
        {
            DateTime d = DateTime.Parse(inputDate);
            string[] convertedDateString = new string[3];
            convertedDateString[0] = pc.GetYear(d).ToString();
            convertedDateString[1] = pc.GetMonth(d).ToString();
            convertedDateString[2] = pc.GetDayOfMonth(d).ToString();
            string currentConvertedDate = string.Format("{0}/{1}/{2}", 
            convertedDateString[0], convertedDateString[1],
            convertedDateString[2]);
            return currentConvertedDate;
        }
}

How can I use my date converter before sending data to datatable?