Can someone in the know enlighten me as to where OT agreements...

Can someone in the know enlighten me as to where OT agreements stand in the event of a third party TO.

For a hypothetical scenario, if someone like FMG/RIO etc were to make a full TO bid for AVZ (KDR style) do they then have to honour the existing Ganfeng OT or can they renege on it if they choose to?

Wondering this because want to know if a party does want to make a TO offer is it then in their interest to do it before too many OT’s are signed or is this not a relevant factor?