Could a creature possibly Hold their Legendary Action?

Legendary actions can be taken only at the end of someone else's turn. #DnD https://t.co/h2EWxNcHsb

— Jeremy Crawford (@JeremyECrawford) January 11, 2018

I thought it was beginning or end?Only at the end

— Jeremy Crawford (@JeremyECrawford) January 11, 2018