Simply removing and replacing the attachments is a bad idea. The trust document should have a section describing how it can be amended. If you try to use some other method for amending the trust, your amendment will not be effective and you will just be shuffling papers. Worse, you could create enough uncertainty and confusion that the beneficiaries will have no choice but to take the matter to a court to interpret the trust. Just follow the amendment provisions found in the trust document. Of course, it's always possible (but unlikely) that the trust says it can be amended by simply replacing Schedule B and Schedule C. In any case, if you have questions, consult a lawyer.