Subject to § 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 § 483-5.