Enlarging from 24" to 72" is simply three times bigger. For every piece in the pattern, subtract the ½" seam allowance from both the length and the width, multiply both by three, then add the seam allowance back to each.
For example, say there is a cut piece in the pattern that is 2½" x 4½". You would subtract the seam allowances (getting 2" x 4" ), multiply by three (getting 6" x 12" ), and add back the seam allowances (getting 6½" x 12½" ). So the new measurement for cutting that piece would be 6½" x 12½". Do that for all the pieces in the pattern.
Probably the best way to keep track of it would be to make a list of all the pattern measurements in one column and then all the enlarged measurements beside them in a second column.