If you're ready to transfer your domain:

1. Verify that at least 60 days have passed since you registered or last transferred your domain.
   In accordance with ICANN rules, you cannot transfer your domain to another provider until 60 days after you register or transfer your domain.
2. Make sure your domain is unlocked.
   For your security, locked domains cannot be transferred. If your domain is locked, visit your Domain Control Panel and click theEdit Domain Locking link. Learn more.
3. Check your administrative contact email address.
   Your new provider will send an email to your domain administrative contact to confirm your domain transfer. If you can't receive the confirmation, you won't be able to complete the transfer! Learn how to update your contact information.
4. Disable Private Domain Registration.
   Private Domain Registration is an optional service that masks personal information that would otherwise be visible in the public WHOIS registry — information that includes the administrative contact email address mentioned above. To ensure you receive your new provider's email, we recommend that you disable this feature. Learn how to disable Private Domain Registration.
5. Get your authorization code.
   To find your authorization code, head to your Domain Control Panel, and click the View Your Authorization Code link. On the following page, you'll see your unique domain authorization code. Print this code, as you'll need it to give to your new provider.Learn more.
6. Contact your new provider.
   When you're ready, contact your new provider to begin the transfer process. Be sure to have your authorization code handy, as your new provider will need it to verify the move. If you have made any changes in steps 2–4 above, we recommend you wait at least 24 hours before contacting your new provider; this will allow time for your updates to be recognized.
7. Cancel your plan.
   Once your transfer is complete, we'll send you an email confirming the transfer (you can also check this status with your new provider — it should take about nine days). When you receive this confirmation, you may cancel your plan. Note that Yahoo! does not automatically cancel your service when you transfer your domain.

Note: Some hosting providers cannot manage domain registrations. If you'd still like to use your domain with this kind of provider, you can redirect, orredelegate, your Yahoo! name servers to point to that provider. In this case, do not cancel your plan, as you'll need it to continue managing your domain through Yahoo!; instead you may downgrade to a Yahoo! Domains plan.

source : help.yahoo.com