IPsec IKE soft lifetime configuration

I have an task to change IPsec IKE soft lifetime duration. For some reason I need to set soft lifetime value to 99% of hard time (or even not in percentage, but in seconds). Haven’t found answer nither in wiki (https://wiki.mikrotik.com/wiki/Manual:IP/IPsec), nor on forum. Can someone help me?
Thanks!

User configurable is only hard lifetime. Soft lifetime is calculated from hard lifetime.

Maybe there is a way to flush only dying SAs manually?
I have a strange problem where one IP unit coudn’t reach another (on opposite side of the tunnel) when new SA generated and old one still dying, but not flushed.

dying SAs is not a problem in this case. Please contact support with attached supout files generated at the time when problem occurred.