TSO/E commands which require a data set name (for example, Edit, DELete, XMIT) first search the current allocations to see if the data set is already allocated to the TSO/E session. If the data set name is already allocated, it will be used by the command. If the data set name is not allocated, it will be allocated based on the standard catalog search order. Therefore, if a data set is desired that is not cataloged, you must use the ALLOCATE command to allocate it to the TSO/E session (see ALLOCATE command). This data set will then be used by all subsequent commands that use this data set name as one of the parameters. Conversely, if an uncataloged data set is allocated to the TSO/E session with the same name as a cataloged data set, and the cataloged data set is desired, you must first use the FREE command for the uncataloged data set so that the standard catalog search order will be used to find the cataloged data set.