I assume we are talking about MirM. In that case if you want to add a new receiver you will need an 802.15.4 modem which we offer here:
This modem allows you to connect software running on your computer to the MirM transmitter board, through this software you program it to communicate with the new receiver.
Alternatively you can ship your MirM transmitter board back to us when you order the new board and we can program it for the new board free of charge.
If you have any other questions on this please let us know.