A mixture of 2/4 and 4/4 time signature problem

[nicholasong]

I was playing a song in 4/4 time and at the middle part threre is a 2/4 measure. I know that if I play in style mode i can always hit the TAP/Reset button to solve the problem. But I just can't do that if I am recording it in Backing Sequence mode or even multi track mode. Please advice . BTW, I have a PSR2100. How do I reset the time bar counting in style mode should there be a 4/4 to 2/4 changes? Thanks