KB32461: The ALTER ATTRIBUTEFORMEXP script does not change the expression for the attribute form with MicroStrategy Command Manager 9.4.x-10.x.

SYMPTOM:
Running the  ALTER ATTRIBUTEFORMEXP script in Command Manager to change an attribute form expression returns the following error:

The attribute form 'attribute form name' was not found within attribute 'attribute name'.

 
CAUSE:
This occurs because the command uses the FORMEXP to identify the attribute form expression in question. The command is designed to change the tables being used by the form expression, not the actual column of the expression.
 
ACTION:
In order to change an attribute form expression of an attribute form, use the "add attributeformexp" script with the overwrite option. 

1. Write out the  ADD  ATTRIBUTEFORMEXP command with the new expression, the mappingmode, lookup table and other identifiers.
2. Execute the command through Command Manager.

Using this command with the overwrite option for the command has the new attribute form expression overwrite the old one allowing the expression to be changed. It does require that the lookup and any additional source tables be specified again even if they are the same ones. An example of the command to change the attribute form expression of an attribute is as follows.
 

ADD ATTRIBUTEFORMEXP "new_expression" MAPPINGMODE MANUAL OVERWRITE LOOKUPTABLE "test_table" TO ATTRIBUTEFORM "test" FOR ATTRIBUTE "test" IN FOLDER "\Schema Objects\Attributes\test" FOR PROJECT "Test project";