You can set the format of member names in date attribute dimensions. If you change the date member name format, the names of existing members of date attribute dimensions may be invalid. For example, if the 10-18-1999 member exists and you change the format to dd-mm-yyyy , outline verification identifies 10-18-1999 as invalid. If you change the date format, you must rebuild the date attribute dimensions and reassociate the data attributes with the base dimension members.
If you have more than one date attribute dimension, to ensure unique member names, consider specifying a prefix or suffix member name format; for example, Product_07012002 and Market_07012002. See Defining a Prefix or Suffix Format for Members of Attribute Dimensions.
To change the date format of members of date attribute dimensions:
Open the outline in edit mode and select the Properties tab.
Under the Boolean and date member names node, select a date format to apply to all date attribute dimensions in the outline.
Click OK.
“Changing the Member Names in Date Attribute Dimensions” in the Oracle Essbase Database Administrator's Guide
Defining a Prefix or Suffix Format for Members of Attribute Dimensions