On the proposal of the academic committee of your programme, the vice-rector for Academic Policy appoints the examination committee that will assess your thesis. The composition of the examination committee must comply with the requirements laid down in the University's Academic Regulations for Doctoral Studies.
Once the defence has been convened, and up to the moment at which it takes place, it corresponds to the chair of the examination committee to take appropriate measures for substitutions (among substitute members) if any member withdraws or is unable to attend. If this is not possible, the chair must suspend the defence and set an alternative date. If the member to be substituted is the chair, it corresponds to the academic committee to appoint another from the rest of the members and substitutes.
The spokesperson (in an examination committee of three members) or spokespersons (in an examination committee of five members) may act via video conference.