If I correctly interpret quotation in your query, the following code should work.
1. You need to convert character to 2 bytes array
2. Then you need to manipulate first byte
3. Finally you need convert manipulated bytes to Unicode character
private char fromPUA(char PUAChar)
{
byte[] bytes = Encoding.Unicode.GetBytes(new char[] { PUAChar });
bytes[1] = 0;
return Encoding.Unicode.GetChars(bytes)[0];
}
private char toPUA(char input)
{
byte[] bytes= Encoding.Unicode.GetBytes(new char[] {input});
bytes[1] = 0xF0;
return Encoding.Unicode.GetChars(bytes)[0];
}