If you also have a TMCC cab-1 remote you can reset the engine I.D. back to 1.
Even without a Cab-1, you can use the DCS Remote to make the engine's TMCC ID# whatever you want it to be by entering: Menu/System/Edit Engine/Edit Address
Then, select the engine and follow instructions regarding the RUN/PROG switch to set the desired TMCC ID#. If you have a copy of The DCS O Gauge Companion 2nd Edition, all the details are on pages 38-39.
This and a whole lot more is all in "The DCS O Gauge Companion 2nd Edition", now available for purchase as an eBook or a printed book from MTH's web store site! Click on the link below to go to MTH's web page for the book!