It is perfectly legal to loan a pattern, sell a pattern, or give a pattern to anyone you choose...if it is the original pattern.
What is not legal is to reproduce a pattern (i.e., make another copy of it) and then loan-sell-give that copy to someone (or for you to keep the copy and loan-sell-give the original away). You can, of course, make templates for your own use. You just can't turn one pattern into two.
Just tell the friend that you will loan her the pattern when you are done with it. Simple really, and perfectly legit.