key variable in determining whether there has been a material change in the guaranty agreement." Roels, 240 III. App. 3d at 582; Zirp-Bumham, LLC v. E. Terrell Associates, Inc., 356 III. App. 3d 590, 606, 826 N.E.2d 430, 292 III. Dec. 289 (2005). [FIN5] "A guarantor takes a risk in exchange for a benefit: when events