The only way I know of is for PC. You have to use Limnono's to trade players. Here is how I do it:
Make sure Limnono is turned on and the roster is refreshed to your current roster you want to edit it.
Select the Player (Reggie) and put him on a team where number 31 is not retired or taken. Make sure Reggie's number is 31.
Put a player from Reggie's new team on the destination team. (Pacers).
Highlight(white bar over player) the player you put on the Pacers.
In Limnono, select the option "Read Hightlighted". Make sure not to click on another player in the list.
Navigate back to Reggie and highlight him, in limnono select "read hightlighted" again.
Limnono's should now display at the top of the tool the two players names, if not repeat the two previous steps.
In Limnono's, select "Trade Players". Reggie should now be #31 on the pacers.