I'm aware that the ADXL345 doesn't have a reset function as such. (Although powering it down seems to work well, as long as you remember to drop the communication lines as well so it doesn't self-power through the protection diodes...)
But it should be possible to write to the individual registers to emulate a full reset. I'm happy to do that myself, but it would seem likely that someone has already written such a function.
Do you have access to such a function? Absent that, do you have any hints on what's required?