You will need to put the same typo for your social security number on the amend that was on the original return. Then when the amend is rejected, change it to the correct social security number. The amend is checking against the original return. When it is e-filed, then the social security number will be checked against the IRS files and it will be rejected.
Print out the amend with the correct social security number and mail it. The first page will have the directions on what to put in the envelope and the address to mail it. Make sure that you sign it.