Not every alteration of, or addition to, a written instrument operates to release the surety. The Indiana Court has held, that in a case where a guarantor executed an instrument reading: "We hereby guarantee," upon the understanding that other guarantors were to be secured; which understanding was not fulfilled, and the instrument was altered before the delivery of the same was made to read: "I hereby guarantee," the alteration itself was held not to be material.28 The Maine Court has held that the rule that the surety is discharged by the alteration of the contract would not apply where the attesting witness saw the note signed, and afterward without the maker's consent, and at the request of the payee, witnessed it, no intent to defraud being shown.29 A surety cannot claim a discharge where he ratifies the alteration, or where after he learns of the alteration he procures an extension of time of payment of the obligation.30 So a surety may consent in advance to the alteration, and the consent would take away his right to claim the release on account of the after effected change.