SELECT FOR UPDATE - release lock?

Hello,

for some tables I am using a "select a,b,c from mytable where x='abc' FOR
UPDATE" query to prevent other servers also modify this data while I am
reading the data and decide to modify the data.

Now sometimes I don't want to make an update. Is there a way to release the
lock. Or is the lock released by simply call commit?

The problem is, that we are using collection pooling. So these datasets
(where x='xyz') would be blocked forever.
How would you solve this? What can i do?

Thank you,

Christian