If the values of parameter does change often, it is good idea to insert them in a table and use Query to extract them for Parameter in report. By doing that we don't have to make changes in report every time if we have to add or remove value. We can simply insert or delete value/s in table those will be extracted by query.
You can use below script to create table for month Names.
Create Table dbo.rpt_MonthName ( MonthName VARCHAR(50)) go insert into dbo.rpt_MonthName values ('January'),('February'),('March'),('April'), ('May'),('June'),('July'),('August'), ('September'),('October'),('November'), ('December') Select * from dbo.rpt_MonthName