Haw. Rev. Stat. § 483-4
Subject to section 483-3, the obligee's release or discharge of one or more of several obligors, or of one or more of joint, or of joint and several obligors shall not discharge co-obligors, against whom the obligee in writing and as part of the same transaction as the release or discharge, expressly reserves the obligee's rights; and in the absence of such a reservation of rights shall discharge co-obligors only to the extent provided in section 483-5.
HRS § 483-4
Where there was no reservation of rights in purchase agreement option by obligee against one co-obligor and no relationship between the co-obligors as joint debtors requiring payment, indemnification or contribution, § 483-5 did not apply; thus, as there was no reservation of rights in purchase option by obligee against one co-obligor, as required under this section, the purchase option which discharged that co-obligor from liability for the balance due under the agreement of sale discharged the other co-obligor as well.89 Haw. 461 (App.),974 P.2d 1051.