Amending a state return is much the same as amending the federal, just need the state 1040X form. Some states have a separate amendment form some just have a box you have to check that it is an amendment.
However, you should not amend your return until you know that the original return has been processed. If you have a refund coming when you receive your refund. Filing an amended return too soon could create problems with the process of the original return.
