There's an old saying: "a locked door keeps honest people out".
So, no, making a change does NOT make your password more secure.
I used to be a hacker (ethical) and part of my job was to ensure security of whole systems, including websites. Every password (and even encoding) can be broken, given enough time and information. But the longer the password, the harder it is to break.
The real trick to making it harder to break is to make the password as random as possible, but still easy enough to remember. But even the most random one can be deduced with enough time and power.