If you create your chord charts in PCO Services by using the chord chart editor, you can also use Music Stand's "Quick Transpose" button to change the notes to another key, even to a Number or Numeral chart.
Your transposed chart will load
Once the Quick Transpose button finishes loading, the chords in your chart will transpose to the key you have chosen. The toolbar at the top will also show both the original key and the transposed key, and the header of the chart will just show the transposed key in the song arrangement information. Tap the Quick Transpose button again to either return to the Default Key, or transpose to any other key in the menu.