You can use this function to parse a string looking for a specific part, which can then be replaced by the new string that you have specified.
string_replace(str, substr, newstr);
Argument Description str The string to be copied. substr The substring within the string to be replaced. newstr The new substring to replace the previous one.
str1 = "Hello Earth";
str2 = string_replace(str1, "Earth", "World");
This will set str2 to str1, but with its instance of "Earth" replaced with "World", resulting in str2 being "Hello World".