This is a follow up to "The meaning of “האב שמחל על כבדו כבדו מחול”?. We learned that (acc. to Rashb"a) the father's מחילה על כבודו totally invalidates the Mitzvah of Kibud Av so the son is not obligated in it (if I understood him right).
For the father's honor to be forgiven, what exactly should he do:
should he declare his intentions publicly in the shul or privately before his sons?
is there a formula of wording so it can be clearly understood he Mochel?
How is the מחילה limited in time if he does not explicitly states that - a day, a month, till the next statement?
The same questions apply to forgiving Rabbi's honor.