Updating a Dashboard

Updating a Dashboard

I want to do one of 2 things - 
1.  Be able to Update the Resolution Time Dashboard to filter out certain Tickets, Subjects, etc.  OR
2.  Use one of my existing reports, I want to be able to add the Resolution Time field. 

I cannot see how to do either of these.  

For that matter, I would like to do the same thing for Initial Response Time.