Probably not, but with the use of a thin, very flemsy fish tape anything is possible. I think you would have to lift the stern at least 2 feet from the trailer to possibly get the centerboard down far enough. That might put a tremendous amount of weight on the forward keel of the boat. I jacked mine up about 6 inches off the trailer during the winter when painting the bottom of the boat.
The center board is approximately 1.5 feet wide and 4 feet long from the keel of the boat when all the way down. The hole the line is tied to is approximately 4-6" down from the keel of the boat and close to the aft edge of the center board with the centerboard all the way down. So when its fully up, I think the line would be located about 8-10" aft of the front edge of the centerboard recess, and about 8-12" from the keel (bottom) of the boat. The original knot on mine was a figure 8 knot tied to the port side of the centerboard. Basically a tight figure 8 knot tied to the end of the line and the opposite end passed through the centerboard and up the chute.
I would recommend looking in the this general area with a flashlight and see if you can see the knot. Once located, jack the boat up little by little until you think you can get to the line. The line came out easily with no need to untie any knot from the port side. A long set of needle nose pliers or a wire coat hanger unwrapped could do wonders removing the old line.
the new line could be taped to the old line end to end with a long piece of duct tape. ONE wrap only with the tape around the lines, done length way. With someone else feeding the line down from the deck, you might be able to get the line through the centerboard hole and down far enough so you can tie another figure 8 knot, and then pull it back up.
Just a theory on how I would attempt removing the line on the trailer. Hope this helps,, let us know how it went...
