Can I split text from one column into to two existing columns in My SQL

SELECT Appointment,
   SUBSTRING_INDEX(SUBSTRING_INDEX(Appointment, ' ', 1), ' ', -1) AS Date,
   SUBSTRING_INDEX(SUBSTRING_INDEX(Appointment, ' ', 2), ' ', -1) AS Time
   FROM go_applicants

which separates the date and time but creates 2 new columns, is it possible to insert/update this split into existing columns in the table. This would allow me then to run this as an event instead and continually update the table.