how to make low BPM intro into higher BPM song

[DJTOYO]

I've been trying to get ableton to remix a song that starts at a low bpm such as 90bpm for the intro then as the song starts it goes up to 120bpm. Is there a way, or would be nice to be able to split main bpm in the song. So you could start the song (warping to that bpm) then make the main bpm go up which in turn will make the warp move so it will be at the higher bpm. something like a rubber band for main bpm would be awesome to have...for other remixing ideas as well. If there is already an easy way to do this link please let me know. thanks
DJTOYO

[re.mark]

Tempo Automation is available in Arrange View.
Look at the [automatable] parameters available for the Master channel. For complete accuracy you can specify the tempo range.

[DJTOYO]

thanks so much for this....awesome