You use the Rename Function dialog box to rename custom-defined functions:
Function name—Box that displays the current name (read only)
Rename to—Box in which you enter the new name (For naming restrictions, see the Oracle Essbase Database Administrator's Guide.)
Overwrite existing function—Option that determines whether functions already using the new name are overwritten
Renaming Custom-Defined Functions
create function (MaxL) in the Oracle Essbase Technical Reference