What is UNGROUNDED IT SYSTEMAND TN SYSTEM . CAN IT BE CHANGED.
I have ACS-04-407A+E200+E208+E904+Q971. vfd
Now I want to change it to E201 can it possible if yes how?
The answer of your question is clearly described in ACS880-04 Hardware manual 3AUA0000128301
You have to disconnect that EMC filter +E200 in case you will use the drive in ungrounded system or a system with high resistance grounding > 30 ohms.
+E200 option could be disconnected at site - there is a picture in the manual above how to do that. You need to disconnect 2 wires, earthed inside the drive.
From the manual I can see +E201 is available for ACS880-04-xxxx-7 types only (690V). Your drive type code is not full?
It is better to ask ABB if you could order +E201 after delivery of the drive (may be that is factory installed option)