Show list of all fields of Entity_A in entry form of Entity_B

Hello,

Basically I want to develop entity change request feature, where Normal user can create change request to update high privileged entity (Here Entity_A). To create change request normal user will user Entity_B form. 

In Entity_B form I want to show list of all fields of Entity_A. How can I achieve this? What kind of structure Entity_B need? Any body has suggestion?

Thanks,

Ashish