The process is quite easy. First download the FlashFix software and then a Windows LiteOn flasher of the drive you wish to overlock.

List of possible overclocks:
LiteOn LTR-40125S -> LTR-48125W
LiteOn LTR-48126S -> LTR-48246S -> LTR-52246S

Not possible overclocks:
LiteOn LTR-48125S/W -> LTR-48126S
LiteOn LTR-48125S/W -> LTR-48246S
LiteOn LTR-48125S/W -> LTR-52246S

Other uses
Convert any LiteOn OEM drive (TDK, SONY, Verbatim, Cendyne, etc..) to an original LiteOn drive. Why you would want to do that? Cause LiteOn usually releases much freuqently firmware than the OEM customers!

So in case you wish to overlock a LTR-48126S to a LTR-52246S, you need to get the windows flasher of LTR-52246S (check the firmware section at the main page), and use the flashfix software (read the included instructions). After run the patched windows flasher and you now have a brand new LTR-52246S drive.

In case you wish to return back, use the LTR-48126S windows flasher (after patching it with the above procedure).