Are you in the correct SIEF?
If you realise that the substance you pre-registered is clearly different from that of the other pre-registrants, you may want to join another substance information exchange forum (SIEF). This may also be the case if you find out that your substance is different during discussions on substances sameness. It is important to remember that whether you find a more suitable SIEF or not, you must register your substance using the correct identifiers, which have to be consistent with the analytical data on your substance, even if they are different from the ones used in your pre-registration.
Take a look at ECHA’s Q&A for more advice.