I assume your use case is similar to that shown below.

The 'bint' data type from the 'analysis' pin of the Data Analyzer node can be converted by using the following script in the downstream Transform node:
tmpType = if('discovered type' == "bint") then "int" else 'discovered type'
emit 'field name' as "OldName",
str(null) as "NewName",
tmpType as "NewType"
I would be interested to understand why your preferred solution is to use the Change Metadata node instead of using the output directly from the Data Analyzer node's 'converted data' pin. The data type on the converted data pin is valid and can be used by downstream nodes - i.e. no conversion is actually required in this case.
Also, have you looked at the Data Converter node which provides automatic data type detection functionality and is provides better performance for larger data sets compared with the Data Analyzer node.