A1 is the start time of an event in hh:mm:ss format.
A2 is a countdown timer until the start time of the event again in hh:mm:ss format

Therefore 'Now' + A2 = A1

I need a formula for OnTime which is going to trigger my macro at the start time (A1).

I cannot use Now + TimeValue because the A1 value will be different each time I use the Workbook and I do not want to have to manually input any data.

I therefore need a code which is going to set the OnTime for my macro as either;
(a) Whatever time A1 is or
(b) 'Now' + A2 (which will always equal A1)