This will be like this, if you have table called UserInfo with column RegistrationDate. Consider 'RegistrationDate' as datetime column. Now suppose it has data for range Jan 1st 2014 to March 31st 2014.
Now if user select 1st March , the data older then 2 months from 1st March will be deleted by below query
Delete from UserInfo Where RegistrationDate <= dateadd(month, -2, getdate())