how to swap wire to relay?

i have a wire that comes from a relay that goes to a 2 wire plug and then grounds out (for HID light setup), my question is the wire in question is a little short and i need to lengthen it,, instead of cutting it can i somehow remove it from the relay plug junction and add another longer wire,, or will it not hurt by splicing a longer section inbetween so i dont disturb the 2 wire plug that is already in place?  i hate to cut a harness to add a wsection in between but it is about a foot short as i need to mount the ballast infront of my gauges (on a motorcycle).

any help is appreciated or other alternative..    thanx     Vic