Change is a fact of life, and that is equally true for documents. They may need to be corrected or revised to accommodate the needs of various signers. An address could be wrong, a name misspelled or a date added, for example.
Any change that is written on a legal document should be initialed by all signers. Any change on a notarial certificate should be initialed only by you, the Notary.
Interestingly, in Hawaii, changes to the document often require the Notary's initials, too.