how to use listagg function in rtf template?

Summary:

Requirement to display a value (output of for loop) in a single row in RTF template, as of now its displaying each value in each row. Needs to be handled in RTF template as we don't have option to modify the query.

Content (required):

I tried like following tag but its not working "<?for-each:DocumentNumber?> <?xdofx: listagg(ReferenceNumber)?> <?end for-each?>"

I am not getting any error but still the data shown in separate rows.

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Code Snippet (add any code snippets that support your topic, if applicable):