find the missing date from output data

Hi Guys,

For Ex,

I have the following ouput rows with column like

Id   Name   Mobile    Signindate

1     AAA      XXX        2012-03-01

2     AAA      XXX        2012-03-02

3     AAA      XXX        2012-03-05

4     AAA      XXX        2012-03-06

5     AAA      XXX        2012-03-07

.

.

the above rows will get based on startdate and enddate parameter like (mar 1,2012 ) to (mar 31,2012)

the Actual output needed is the missing date of Signin ,here in above ex ,it will be march 3 ,march4

Final Output is,

Id   Name   Mobile    Signindate-Missed date

1     AAA      XXX        2012-03-03

2     AAA      XXX        2012-03-04

how to do in tsql

any help is needed 

Thanks

r.b