In your output/readout I only see "sda" indicating that you have one HDD on that machine. I don't see another HDD from the output.
If you have a memory stick or external HDD it would show as "sdb" and a 3rd usb device would show as "sdc" so forth and so on.
Looking at this partition that you have on you hard disk drive-
/dev/sda5 95G 27G 63G 30% /u07
Yes, you can re-partition it.
First what ever you have on that partition you may want to back it up or put in on a memory stick or some other type of hardware (extern HDD or something before you manipulate it.
You can use G-parted to delete that partition and than create a new one and make the size of it whatever size you prefer.
Can i partition /dev/sda6 once again..?
Yes, but you will have to do as I mentioned above. Unless you are not concerned about what's on that partition then you can go ahead and resize it-
For example lets say I have a HDD with 3 partitions-
- /dev/sda1 * Linux boot partition size 20 GB
- /dev/sda2 Linux root partition size 4 GB (gigabytes)
- /dev/sda3 Linux swap partition size 2 GB
Using G-pared I could click on and highlight the 20 GB partition and resize it to 24 GB if I wanted to.
However I would have to delete the 4 GB partiton before creating the 24 GB partition-- (just and example)
What distribution are you using?