If you want to transfer the balance one recon.account to another, then in that case first check which vendors have balance against the old & new recon.account, later you have to transfer these balances vendor to vendor not GL to GL. Because these GL accounts are recon.account and you cannot post directly postings.
Since both the source and destination GL accounts are set as reconciliation account for vendors, reclass of balance from one GL to another will be posted to the vendor accounts where the balances reside, not directly to the GL accounts.
Check first the items consisting the balance per vendor, if these are normal or SGL items. You might need to consider this in your reclass entry.
Hope this helps.