The only time i have done this has been with 100lb JB hollow and splicing a new length on.
With solid i would just reverse the braid. If you need to top up the spool slightly put on some backing first.
You should be ok to strip off and replace 150m of braid for a one off trip. You would be pretty unlucky if you hook a GT which takes you down to the knot, very few run that far.