De La Tour was contractually obligated to pay Hochster as his tour guide, and he De La Tour is contractually obligated to have Hochster begin work as his tour guide on June 1. He fails to perform this promise if on June 1 he does not allow Hochster to begin work as his tour guide. On May 11, he announces that, when the time comes to perform on June 1, he will not do so. The announcement is a repudiation. This is distinct from the failure to perform, which can only occur on June 1.