I have an application that contains section access on clientname. on login dynamic data reduction happens and data gets reduced. however I have a requirement that for a specific chart I need to get full data overcoming the section access. how is this possible . also this chart needs to be updated with any filter selections.. I.e it should be associated to all dimensions ..
I don't think you can "break" section access as such.
The approach I've taken in similar situations is to load another copy of the data which includes an extra section access key and give all users that key.
For example if securing using department ID's which are numbers, reload the data with a new department (eg 999) and in the section access load give all users access to 999 in addition to what they already have.
Your existing expressions may need to filter out the new department to avoid double counting. You may be able to pre-aggregate the data copy if performance is an issue.