Anyone with a second-dose appointment date on or after Aug. 28 is being asked to reschedule their appointment to a date before then, as there should be enough available appointments and vaccine supply prior to that date to accommodate them. These appointments can be re-booked the same way they were initially scheduled, through the Ontario.ca/booking website, or by phone at 1-833-943-3900. The health unit also said there remain hundreds of available spots at two upcoming walk-in clinics— one of which is scheduled for the Benson Centre in Cornwall on Saturday, July 17, from 9:30 a.m. to 12 p.m., and 1 to 2:30 p.m. Only those whose first-dose appointments were at least 28 days ago for Pfizer-BioNTech or Moderna vaccines, or at least eight weeks ago if the first dose was AstraZeneca, can get their second dose at a walk-in clinic.