YouTube accounts created before May 2009 can be linked to any Google account of your choosing. If you have one of these old YouTube accounts and you've already linked it to a Google account, you can unlink it and then link it to a different Google account. YouTube accounts created after May 2009 cannot be modified in this manner because they are, in fact, Google accounts. If you've unlinked an older YouTube account, you will be prompted to link it to a Google account the next time you sign in to YouTube.
Open a Web browser and go to "Youtube.com/my_account_unlink".
Sign in to your YouTube account by entering your username and password.
Click the "Unlink My Accounts" button on the page that appears after you have logged in to YouTube.
Open the "finish link upgrade" page at Youtube.com.
Provide a new Google account name that you'd like to link to this YouTube account. Input the account name into the space provided and press "Enter."
Open a Web browser and go to "Youtube.com/my_account_unlink".
Sign in to your YouTube account by entering your username and password.
Click the "Unlink My Accounts" button on the page that appears after you have logged in to YouTube.
Open the "finish link upgrade" page at Youtube.com.
Provide a new Google account name that you'd like to link to this YouTube account. Input the account name into the space provided and press "Enter."