When Ron Howard was still on the show? Instead, we get an episode where Richie marries Laurie Beth by phone with Fonzie standing in as his proxy. Then, they could have said that Richie and his new wife moved away without having him in the army.

I however, read (https://web.archive.org/web/20140406105924/http://forums.televisionwithoutpity.com/topic/3116785-happy-days-where-the-shark-was-first-jumped/page-18#entry15558461) that when Ron Howard knew he was leaving Happy Days, he told Lynda Goodfriend first, so she could resign her contract before he told the producers. That way, they had to keep her even after he left.