How would you deal with a player wanting to change character in the middle of a campaign?

@ChrisPerkinsDnD How would you deal with a player wanting to change character in the middle of a campaign?#dnd5e #dungeonsanddragons

— Diaton Lerkis III (@diaton_lerkis) October 22, 2016

I would help the player find a way to retire the old character and integrate the new one. #wotcstaff https://t.co/fB4B7iVKho

— Christopher Perkins (@ChrisPerkinsDnD) October 22, 2016