How can I transfer the funds that I’ve delegated back to my manager account?

Select the kt account associated with the baker you’d like to withdraw from and use the “Withdraw” tab to move tez to your manager account. Be sure to use a fee of at least 0.005 XTZ and transfer less than the total balance on the account, leave behind 0.000001 XTZ.

Don't forget to use the latest supported version of Galleon listed on the official download page.