Using the System.String.Replace method, you can replace part of a string with another string.

string s = "Hello World";
 s = s.Replace("World", "Universe"); // s = "Hello Universe"

All the occurrences of the search string are replaced.

This method can also be used to remove part of a string, using the String.Empty field:

string s = "Hello World";
s = s.Replace("ell", String.Empty); // s = "Ho World"