[Solved] Changing Tempo

Let's suppose I have recorded an acoustic guitar part to a metronome's click, except that at the very end I disregarded the click and slowed down for a more expressive ending. Now I want Sonar to change tempo (slow down) at the end so that any MIDI instruments which I might want to play in sync with the guitar will do so. I know how to change the tempo, but that's pretty much hit or miss. In other words, I would be guessing as to what numerical values to enter in order to make Sonar stay in time with my guitar track. Is there instead some more direct way to line up, for example, Sonar's downbeats with my guitar's downbeats? It seems to me that I read something about this at one time.
 
Thanks.

That was it! Thank you.

konradh
As anyone who listens to pop music should know, where you got off track was trying to be expressive.

 
FBB did a nice video on Youtube on using this function, IIRC.