If you create your chord charts in Services by using the Lyrics and Chord Editor, you can quickly change the notes to another key--even to a Number or Numeral chart.
Tap the screen to show the toolbar. If your chart was made by the Lyrics and Chord Editor, you'll see its key in a circle.
Tap the circled key to transpose it.
Choose a different key from the listed options.
Select Number or Numeral to change format of the chart.
Once the PDF loads, the chords in your chart will transpose to the key you have chosen. The header of the chart will show the transposed key in the song arrangement information. Tap the circled key again to either return to the Default Key or transpose to any other key in the menu.
Transposing the key doesn't affect the plan. The song in the plan will still show the originally assigned key.