User blog comment:Fairingrey/March 20, 2015 Another Tiny Future Content Update + Wiki Stuff/@comment-172.9.190.84-20150321182627/@comment-25036392-20150322234153

You can simply transfer your rerolled units by using the bazaar, if that's what you would like to know. I personally recommend using two devices for this process, one for your main and another for your other account, but that's just my personal preference and I'm aware some people just don't have two devices.

To keep things safe, though, put up the unit you would like to trade over by putting up an unit that's one rarity lower from your main for the desired unit(s) from your reroll account (E.g. If your desired unit is a 5*, it's recommended putting up a 4* in bazaar to funnel the 5* over to your main. Again, to keep things safe).

However, keep in mind 7*s can't be traded as of now. They might become tradeable in the future, but I can't tell for sure.