Yes. You can replace the controller with same controller from another server. "5CT6D" is the part# of H710 Mini supported on R720xd. You can refer below link on the instruction. It is recommended to have latest BIOS, PERC and iDRAC FW installed before replacing the card. [URL] 
Hello.  I have problem with my PERC H710 Mini (Embedded) in the dell r720xd(not present in list devices and cannot load due to stuck on "Initilializing firmware interfaces"). So my questions can I replace PERC H710 Mini (Embedded) with another one from another identical server? Thanks.
Replace PERC H710 Mini (Embedded)