1. In SONG mode (with the desired song selected), press the EDIT button
2. On that first EDIT page, look for the "TimeSig" parameter. Use the cursor buttons to select than option and turn the rotary dial to change 4/4 to 3/4 (or whatever meter you'd like).
3. Press the EXIT button, when asked to "save changes" press the YES soft-key to proceed.

Quantize options can be found Song mode by pressing the MISC soft-key. There you can change QUANT = OFF to any percentage (a higher percentage will more rigidly pull notes to an exact beat). The GRID parameter below QUANT sets the note value to which Quantize will snap to (could be 1/4 notes, 1/8 notes, etc).