here is a form to request penalty abatement.
You may either use a form or may attach a note (better type instead of hand written).
File a form 843 -http://www.irs.gov/pub/irs-pdf/f843.pdf.
When form 843 is filed to request an abatement of penalties - you would need to provide a reasonable cause.
to request the accuracy related penalty to be abate based on reasonable cause. If you provide the reason like I forgot - I do not think it will be considered as reasonable - so be careful when prepare an abatement request.
The best would be to use a local CPA who will evaluate your situation and help with preparation of the abatement request.
Here are some common examples that the IRS provides for considering individuals for penalty abatement.
-- Death of the family member
-- Unexpected absence (in prison, hospital, etc)
-- Casualty event (fire, flood, etc)
-- Unforeseen circumstances (divorce, etc)
-- Incorrect advice from a tax professional
-- Incorrect advice from the IRS
-- An accuracy related error when acting with ordinary business care and prudence
-- Other (reasons are not limited by the above list)
Specific regulations and wording regarding Reasonable Cause - see IRM (Internal Revenue Manual) 184.108.40.206.2 (11-25-2011)
I hope that helps.