a coaching change does not make a NLI null and void. but substantiated recruiting violations do.. Cal had substantiated recruiting violations shortly after he left Memphis. I don't think you can modify a NLI or have clauses added to it.. a NLI is a NLI, standard from the NCAA. if that were the case, college athletics would be a **** storm.
From a NLI: "I understand I have signed this NLI with the institution and not for a particular sport or coach. If a coach leaves the institution or the sports program (e.g., not retained, resigns), I remain bound by the provisions of this NLI. I understand it is not uncommon for a coach to leave his or her coaching position."