From API not possible to go to AT

My XBEE programmed as XB24-B 2,5 coordinater 1147
Now it is not possible to change to coordinater AT 1047.
What are the tips and tricks to reprogram the xbee?
Now the are useless.

Version 1147 would be an API type firmware load. When converting from 1147 to 1047, make sure the “Enable API” box is checked on the PC Settings tab of XCTU.

XCTU will error after the 1047 (AT) has been programmed onto the module, but you can ignore this. Once the 1047 firmware update is done, go back to the PC Settings tab and now UN-check the “Enable API” box. You should be able to query the 1047 firmware successfully at this point.

Tanks for the replay.
The problem is part of a more difficult situation.
I have two XBEE,s running on a arduino and configurate as coordinater and router end device. Running perfect.
Now I like to implement a extra xbee to the network. As far as I understand I need to updated to ZB with API .
No longer serial date te read from the receiving radio?
What data is needed to see what am I doing wrong.
Wanted situation: Receiving xbee to display data
1 pcs enddevice sending serial data
a 2 nd enddevice sending serial data

ps. I programmed the whole back to znet2,5 coordinater and router/end device and it is working again.
checking the API box I did.