In SQL Server, to concatenate values, you need + between the values:
DATENAME(MONTH, DesiredDate) +' '+ DATENAME(YEAR, DesiredDate)
You may need to use &' '& , which will add spaces between the values:
DATENAME(MONTH, DesiredDate) &' '& DATENAME(YEAR, DesiredDate)
Change # 1 based on your comment, you can use the following in the Expression window:
=MonthName(Month(Fields!desireddate.Value)) &" "& Year(Fields!desireddate.Value)
Note. I just checked this in SSRS 2008 and it returned the result you want.
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