In short, **No, it's not possible**.

From [SSRS 2008 Column issue when exporting to a CSV file][1]:

> For csv export, the header of a column is determined by the `DataElementName` property of the textbox which actually contains the data. If the `DataElementName` property is not explicitly set by the user, DataElementName automatically gets defaulted to the value of the `textbox.Name` property.  
>
> That being said, I believe you're getting this issue because RDL has a restriction that both a `reportItem.Name` and `reportItem.DataElementName` property must be [**CLS-compliant identifiers**][2]. The headings like `"Phone #"`, `"Other Name(s)"`, etc... are not CLS-Compliant.
>
> You can verify this by opening up the report in BIDS or RB and trying to set the DataElementName/Name property of the textbox containing the data to those names.  
>
> You will get an error which states the following: 
>
> `Property Value is not valid. Specify a valid name. The name cannot contain spaces, and it must begin with a letter followed by letters, numbers, or the underscore character (_).`

There is a Microsoft Connect Issue about this, but unfortunately it looks like it won't be acted on.  
**See**: [Use of expressions for DataElementName property (for CSV Export)][3] 

[1]: https://social.msdn.microsoft.com/Forums/sqlserver/en-US/bc7bcae8-cce2-4626-8cb9-132a239a4ab8/#f9bd33ae-6d92-4050-94d8-92c6e26e00cc
[2]: http://www.unicode.org/unicode/reports/tr15/tr15-18.html
[3]: https://connect.microsoft.com/SQLServer/feedback/details/732034/

By default, csv takes the text box name as the csv header name for the columns. The text box does not allow a space. 

How do I make a different header than the text box for the csv?  
Is there a way to display comma in the header when exported to csv?

**Note**: The solution has to be only for one report; not global.
