ORA-00828: specified value of shared_pool_reserved_size inconsistent with internal settings

ORA-00828: specified value of shared_pool_reserved_size inconsistent with internal  settings
Cause: Unable to set shared_pool_reserved_size to specified value if sga_target  set, either because
the specified value is too small, or because it is too large for the  current internal size of shared pool. More details can be found in the alert log.
Action: If possible, do not set shared_pool_reserved_size without setting shared_  pool_size if sga_target set. Examine the alert log for information about current  internal size of shared pool, and valid range of values for shared_pool_reserved_  size.