Hello and welcome, Gayle.
By "release pending messages" I'm wondering if you mean in sms there are drafts not yet completed and sent. Or do you mean something about email?
Either way you can go to the folder in "my files" and remove them, as long as you know the path, but that depends on what kind of phone/tab you have.
You can also use the sms or email utility to remove them if they are not sent items that are stuck in the system because of a carrier glitch.