I want to change lawyers on my case I've already signed forms what do I do to undo the agreement?

You always have the right to substitution of counsel. If you are saying that you signed forms to substitute counsel then let your new attorneys handle the prior agreement you may have had with your first attorney. I am not sure what you mean about "undoing the agreement". If you had a contingency agreement, then the new attorney will be entitled to whatever commission they and you have negotiated. The former attorney may have a lien on any settlement or judgment based upon 1) expenses they laid out, 2) settlements that they might have already negotiated. For instance say your first attorney had a settlement offer of $10K that you refused. Your new attorney gets a settlement of $50K. Your former attorney may be entitled to a fee based upon the first offer of $10,000 that that attorney's firm negotiated. Of course, if there were no offers, it would not matter.  Another possibility is that you have an agreement to pay the first attorney hourly fees. If there were still outstanding hourly fees owed to the first attorney, that might also be a lien against any settlement or judgment your new attorney may get on your behalf.