(a) If a person entitled to enforce an instrument releases the obligation of a principal obligor in whole or in part, and another party to the instrument is a secondary obligor with respect to the obligation of that principal obligor, the following rules apply:
(1) any obligations of the principal obligor to the secondary obligor with respect to any previous payment by the secondary obligor are not affected. Unless the terms of the release preserve the secondary obligor's recourse, the principal obligor is discharged, to the extent of the release, from any other duties to the secondary obligor under this chapter.
(2) unless the terms of the release provide that the person entitled to enforce the instrument retains the right to enforce the instrument against the secondary obligor, the secondary obligor is discharged to the same extent as the principal obligor from any unperformed portion of its obligation on the instrument. If the instrument is a check and the obligation of the secondary obligor is based on an indorsement of the check, the secondary obligor is discharged without regard to the language or circumstances of the discharge or other release.
(3) if the secondary obligor is not discharged under paragraph (2), the secondary obligor is discharged to the extent of the value of the consideration for the release, and to the extent that the release would otherwise cause the secondary obligor a loss.
(b) If a person entitled to enforce an instrument grants a principal obligor an extension of the time at which one or more payments are due on the instrument and another party to the instrument is a secondary obligor with respect to the obligation of that principal obligor, the following rules apply:
(1) any obligations of the principal obligor to the secondary obligor with respect to any previous payment by the secondary obligor are not affected. Unless the terms of the extension preserve the secondary obligor's recourse, the extension correspondingly extends the time for performance of any other duties owed to the secondary obligor by the principal obligor under this chapter.
(2) the secondary obligor is discharged to the extent that the extension would otherwise cause the secondary obligor a loss.
(3) to the extent that the secondary obligor is not discharged under paragraph (2), the secondary obligor may perform its obligations to a person entitled to enforce the instrument as if the time for payment had not been extended or, unless the terms of the extension provide that the person entitled to enforce the instrument retains the right to enforce the instrument against the secondary obligor as if the time for payment had not been extended, treat the time for performance of its obligations as having been extended correspondingly.
(c) If a person entitled to enforce an instrument agrees, with or without consideration, to a modification of the obligation of a principal obligor other than a complete or partial release or an extension of the due date and another party to the instrument is a secondary obligor with respect to the obligation of that principal obligor, the following rules apply:
(1) any obligations of the principal obligor to the secondary obligor with respect to any previous payment by the secondary obligor are not affected. The modification correspondingly modifies any other duties owed to the secondary obligor by the principal obligor under this chapter.
(2) the secondary obligor is discharged from any unperformed portion of its obligation to the extent that the modification would otherwise cause the secondary obligor a loss.
(3) to the extent that the secondary obligor is not discharged under paragraph (2), the secondary obligor may satisfy its obligation on the instrument as if the modification had not occurred, or treat its obligation on the instrument as having been modified correspondingly.
(d) If the obligation of a principal obligor is secured by an interest in collateral, another party to the instrument is a secondary obligor with respect to that obligation, and a person entitled to enforce the instrument impairs the value of the interest in collateral, the obligation of the secondary obligor is discharged to the extent of the impairment. The value of an interest in collateral is impaired to the extent the value of the interest is reduced to an amount less than the amount of the recourse of the secondary obligor, or the reduction in value of the interest causes an increase in the amount by which the amount of the recourse exceeds the value of the interest. For purposes of this subsection, impairing the value of an interest in collateral includes failure to obtain or maintain perfection or recordation of the interest in collateral, release of collateral without substitution of collateral of equal value or equivalent reduction of the underlying obligation, failure to perform a duty to preserve the value of collateral owed, under Chapter 9 or other law, to a debtor or other person secondarily liable, and failure to comply with applicable law in disposing of or otherwise enforcing the interest in collateral.
(e) A secondary obligor is not discharged under subdivision (a)(3) or subsections (b), (c), or (d) unless the person entitled to enforce the instrument knows that the person is a secondary obligor or has notice under § 4-3-419(c) that the instrument was signed for accommodation.
(f) A secondary obligor is not discharged under this section if the secondary obligor consents to the event or conduct that is the basis of the discharge, or the instrument or a separate agreement of the party provides for waiver of discharge under this section specifically or by general language indicating that parties waive defenses based on suretyship or impairment of collateral. Unless the circumstances indicate otherwise, consent by the principal obligor to an act that would lead to a discharge under this section constitutes consent to that act by the secondary obligor if the secondary obligor controls the principal obligor or deals with the person entitled to enforce the instrument on behalf of the principal obligor.
(g) A release or extension preserves a secondary obligor's recourse if the terms of the release or extension provide that:
(1) the person entitled to enforce the instrument retains the right to enforce the instrument against the secondary obligor; and
(2) the recourse of the secondary obligor continues as if the release or extension had not been granted.
(h) Except as otherwise provided in subsection (i), a secondary obligor asserting discharge under this section has the burden of persuasion both with respect to the occurrence of the acts alleged to harm the secondary obligor and loss or prejudice caused by those acts.
(i) If the secondary obligor demonstrates prejudice caused by an impairment of its recourse, and the circumstances of the case indicate that the amount of loss is not reasonably susceptible of calculation or requires proof of facts that are not ascertainable, it is presumed that the act impairing recourse caused a loss or impairment equal to the liability of the secondary obligor on the instrument. In that event, the burden of persuasion as to any lesser amount of the loss is on the person entitled to enforce the instrument.