Yes Bob, that's possible.
In this posting I assume that you have your song recorded using the Easy Record mode, so you can easily reproduce the procedure.
Make your recording at tempo 86. After pressing the button REC STOP press Program Menus, press Sequencer, press Record & Edit, press Step Record, press Track6/CTL (with easy record track 6 is always assigned as the control track), the first data that is displayed is Total Expression, press the cursor right button so that the tempo=86 is displayed, change the value to 125 and save the sequence the normal way you save to disk or SD-card. When you load the sequence again it will play at tempo 125.
Mind this: when you use the value button, the new tempo data will be written immediately into the track; you can also use the tempo/data wheel however, you need to press the YES button that appears to confirm writing the new tempo data into the track.
If a sequence (midifile) has no control track, you have to assign one and change the tempo in that track the same way as described above.
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