The release bend is also sometimes called a reverse bend. You actually start with the note bent before picking it, then release the pressure with your fingers and allow the note to fall to its natural pitch. The symbol for a release bend is a curved downward arrow and the symbol "R".
Here is a lick which uses the release bend.
These next two licks use both the bend and the release bend.
To end this lesson, here are a couple of licks which make use of all the techniques covered so far.
In this one you will need to keep the first finger covering both the first and second strings at the 5th fret and roll the finger between the two notes instead of jumping from one string to another.