How to change track tempo without changing it for the existing midi tracks?

I`ve created some midi tracks I need that sound about 70 bpm, but the track tempo at the time was set at 120 bpm. How do I change it from 120 to 70 without affecting all the midi tracks?

Change the Timebase on the Tracks from Musical to Linear. Now the Track will be anchored to mm:ss instead of Bars & Beats.

Now change the Project’s Tempo. The Events on the Linear Tracks should not move in time when this happens, but the Bars & Beats position will change.

You might want to add a 2nd Ruler to the Project so you can see where things are located on both timescales.