Sharepoint change Content Type in Sharepoint Designer using workflow -

i trying change document content type. must use workflow, , best way workflow create in sharepoint desingner. know how programatical in visual studio

i know old question, figured out:

you can using spd workflow (spd 2007 or 2010). can call content type field in 2 ways:

1. in workflow, use "if [field] equals [value]" or "set [field] [value]"

2. for "if" statement, field called "content type". "set" statement field called "content type id". in either case can assign value based on available content types.

you need enable content types on list or library settings. here's example workflow based on custom list record accounts payable entries:

list column: request type (choice column choices of reimbursement, department expense, other)

list content types: default, accounts payable, accounts receivable

if [request type] equals [reimbursement] set [content type id] [accounts payable] 

when workflow fires, set content type accounts payable if request type column equal reimbursement.