Pie update percentages from a copy

Some pies are updated frequently. Having a button to update percentages from a copy would simplify the following process:

  1. Ensure all fractional positions are in a pie.
  2. Export positions from old pie.
  3. Import existing positions into new copy.
    4.Rebalance pie
  4. Delete old pie.

If some positions have been removed from old pie then additional steps are required.

2a. Identity redundant positions.
2b. Sell these positions
2c. Add proceeds from sale to pie if the system allows

etc, etc