are you using 3rd party theme through WinterBoard?
If yes, here is what u need to do:
- SSH to your iPhone (google "OpenSSH iPhone")
- Navigate to /root --> Library --> Themes
- Find the 3rd part theme u want to change
- Go to folder "Bundles" --> "com.apple.springboard" --> "en.lproj"
- Open the file "SpringBoard.strings"
- You will see a string similar to this: "AWAY_LOCK_LABEL" = "slide to unlock...";
- Change the "slide to unlock..." part and remember to keep the quotation marks
- Save the file and restart the SpringBoard (and simple restart would do it)
It is much easier to edit and existing Lock Screen theme using the steps above and creating your own theme. At least that is the perception I have, but its doable either way.
If your answer to the question in the beginning was no, then I do not really know how to change it. I am interested to know as well.
I hope this was helpful.
Btw, the above steps worked for me out of personal experience and messing around in the phone files lol. If anyone knows a better way, please let us know.