In EthOS, you request the signature of the Principal Investigator (P.I.) as part of the final step in submitting your application. The PI receives an email notification when you have requested their signature, and can access the application directly from the email to complete the signature declaration step. Once the PI has signed the application, it is automatically submitted to EthOS. For more information, see the Create & Submit an REB Application [1] User Materials in the  Signatures and Submitting Applications [2] section.