(warning: this is very dangerous if you do not know what you are doing)
Yes, you can, but I do not recommend it (though I did it a few times, mostly to transfer a partition to another HDD).
dd if=/dev/sdaA of=/dev/sdaB
will transfer the data from
sdaB, but no checking will be done, all the partition will be copied (even the empty space), you must be sure that
sdaB is bigger or equal
sdaA (otherwise you overwrite the beginning of following partition), and the system most likely won't boot - you'd have to boot from rescue CD/USB, mount
/dev/sdaB, modify grub configuration and re-run grub-install. And optionally resize the filesystem to reclaim any remaining space.
It is much better to create the filesystem on /dev/sdaB and copy the filesystem contents. You'd still have to re-run
grub-install, but at least this is much safer.