16th triplet equals 16th straight note

I want to set the tempo as follows.16th triplets at 120 and afterwards set the tempo where each 16th triplet equals a 16th note.Is there a way to do this in tempo track?
thank you

Two ways…
a) In the Tempo Track Editor window, open the “Process Bars” dialog, set the desired bar range, set “Action” to “Reinterpret Bars”, change the time signature from 4/4 to 12/8, then hit “Process”,
b) Set all tracks to Linear Timebase as opposed to Musical Timebase (toggle the “quarter-note” for each track icon into the “clock” icon), then change the tempo from 120 BPM to 180 BPM (=120 x 3/2).