pelo que pesquisei
sending off = expulsar (pesquisa no forum)
senf off = enviar, mandar, acompanhar (wordreference)
an occasion to express good wishes and say goodbye to someone who is leaving a place
mas não consigo pensar em uma palavra adequada para essa sentença.
"We’ve lived through so much change in this building and so much history that it’s going to be sad. And I hope she gets a proper send off, this building."