Is there any open source Ticket Management System in ASP.NET

Hi , I want to get it know is there any open source Ticket Issuence system in asp.net which is open source and freely available to modify , kindly let me know so that i can fulfill my requirement by modifying it , I have an IT department where we deals with issues for other office staff but any one can come and ask to resolve the issue but i need some ticketing system so that user can issue the ticket and then based on priority based we deals with them.