Say it is no problem
Reassure them first, then move to times.
Offer two or three times
Give specific options in their time zone.
Restate the goal of the call
Remind them what you will cover, so the new time still feels useful.
Send the new invite
Confirm the new time and attach the calendar invite.
Offer a written alternative
If time is short, send a short guide and a way to ask questions.