You can have one hotkey to partial, cancel the current stop, and reset it with remaining position at break even.
This will sell 10% of your position when long and do the rest mentioned above:
CXL ALLSYMB;Route=LIMIT;Share=Pos*0.10;Price=Bid-0.05;TIF=DAY+;SELL=Send;ROUTE=STOP;StopType=Market;StopPrice=AvgCost;Share=Pos-share;TIF=GTC;SELL=SEND