You can put in an ERR to anywhere. You would have better chance as GS13 but there is no requirement as long as the office is looking for the grade you are currently (assuming GS12). Not possible to ERR to a higher grade (cannot get a promotion). You can however ERR to a LOWER grade (13to 12) or (12 to 11) but I would not recommend doing that unless the situation is dire. Read the contract, there is an article on ERR’s. Good luck!