You shouldn't maintain multiple accounts (check out our Terms of Service), but if you've accidentally created a second account, you can copy or download content from the duplicate account and re-post it from your main account. Our Support team can't merge two user accounts or move content from one user account to another.
Once you've moved your content to the correct account, you should close the duplicate account to remove the possibility that another Yelper or one of our moderators notices your accounts and thinks you're up to no good. To close the duplicate account, please contact our Support team.