I'm happy to assist you with information on making corrections on the 1099's. If you have E-filed 1099s, it doesn't have the option to make corrections. You can, however, make corrections in a printed copy and send it by mail to the IRS.
Note: If the contractor of the 1099 form wants the information corrected, you'll need to provide the amended return to the contractor and file it again.
To categorize a 1099 account, you need to manually choose it while preparing your forms. In the Categorize payments to contractors (or 1099 vendors) window, you need to select the box so you'll be able to choose the correct expense account you use.
Furthermore, amending a 1099 form will require you to print a new paper form and send it directly to the IRS. You can pull up the 1099 Transaction Detail Report in the Reports menu for your reference in completing its details.