You can display a list of the transaction codes processed since you logged on (called a history list), and then choose a transaction code from that list.
As of Release 4.6, the command field is closed by default. To display it, choose the arrow to the left of the Save icon:
The command field appears:
To hide it, choose the arrow to the right (outside) of the field.
The history list appears, displaying the transaction codes for all the transactions you have accessed in all of your sessions since you logged on. A sample history list is shown here.
This takes you to the initial screen of the task associated with that transaction code.