What is waiver of right?

Article 6 of the New Civil Code. Rights may be waived, unless the waiver is contrary to law, public order, public policy, morals, or good customs, or prejudicial to a third person with a right recognized by law.

What is a waiver of right? It is the relinquishment of a known right with both knowledge of its existence and an intention to relinquish it. (Portland v. Spillman)

What are the exceptions?

[1] If the waiver is contrary to law, public order, public policy, morals or good customs
[2] If the waiver prejudices a third person
[3]If the alleged rights do not yet exist
[4] If the right is a natural right

[5] If the right is not known to the person waiving it

[6] If the waiver is not clear and unequivocal
[7] If the person waiving it has no capacity to do so