You can copy one pattern to another in exactly the same way as you can in, say, the Redrum.
Go to the pattern you want to copy and in Windows hold control and then press 'C', then go to the empty pattern (or destination pattern) and hit control + 'V'.
The process is the same on a Mac --- just use the Option key insead of the control key.
This procedure is in your manual, which is chock full of other very good information about Reason procedures.
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