Once the previous step of anti-plagiarism control has been completed, the process of external evaluation of the thesis draft begins.
The draft of the thesis (V1) will be sent to a group of researchers from outside the UPV and experts in the topic of the thesis.
The initial proposal of professors who will review the thesis can be done by the supervisors of the thesis, although it will always be the responsibility of the Academic Committee to approve the final proposal, which may or may not coincide with the initial one.
You can check the detail about the process in this link.