[otrs] Diff between PendingDate and Due date?

Hello, Can you tell me, what is difference between 'PendingDate' and 'Due date'? Under what situation, should each one be used ? thanks... Pradumna Maheshwari =====-----=====-----===== Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the intended recipient, any dissemination, use, review, distribution, printing or copying of the information contained in this e-mail message and/or attachments to it are strictly prohibited. If you have received this communication in error, please notify us by reply e-mail or telephone and immediately and permanently delete the message and any attachments. Thank you