Apply or set font size,font name for particular style using open XML in C#.net or VB.NET

Hi,

I have word document.In that document has many style(like normal,heading1,heading2 etc).I want to Apply font size,font name for particular style using open XML.For example i want to apply font size,font name for normal style in that document using open XML in c#.net or vb.net.please provide solution....