Danby guaranteed that the Osteopathic Association would receive credit for bank loans totaling $55,000. The Association, a charity, was using the funds to build a hospital. After the hospital had used $31,000 of the credit available, Danby became dissatisfied with the construction of the hospital and attempted to withdraw his guarantee for the rest of the promised funds. If the Association decides to sue to prevent Danby from withdrawing the rest of the funds, which party will be successful and why?