It is possible with Node Convert.

Node Convert adds a menu tab "Convert" on the node view page, i.e. node/1/convert, which gives the ability of converting the node from it's current node type, to another node type. Also it gives the ability of transfering all the custom cck field values of the current node type, to the destination cck fields, or discard them. As of 5.x-1.4 you can bulk convert many nodes of the same type, to another one that can be accesed in Administer-> Content -> Convert Nodes.