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We are migrating to a single Endicia account model and it will not be possible to keep the Endicia First Class Domestic account open much longer. The migration should be fully complete in the next couple of weeks.
I would recommend cancelling any unused labels that you need to cancel from your Endicia First Class Domestic account and then exporting the transaction reports so you have record of your transactions prior to closing the account.
Steps for exporting your transaction reports can be found in the following article from our Knowledge Base: How to: Obtain my Endicia refund and transaction history
Once you have cancelled any unused labels and exported your transaction reports, you should be ready to migrate your account.
You can see the full details of the migration here: FAQs: Migrating to a single Endicia account