Thats why you suggest an alternate time, so that the onus is on them. Alternately if you know someone competent and willing to attend to make sure it goes right

Thats why you suggest an alternate time, so that the onus is on them. Alternately if you know someone competent and willing to attend to make sure it goes right, ask them if they'll go. Whether you come off as disinterested or busy is up to you.