Manual fail over?

We have 2 BIG-IPs (BIG-IP 9.4.3 Build 1.4 Final ) setup in Active/Standby. We want to take down the secondary, and move it physically then let the secondary take over as primary so we can also move the primary.

 

 

If I click on "Force to standby" on my primary in the web interface under System -> High availability, will the secondary automatically take over?

 

 

Is there a better way to do this?

 

 

Also how quickly should I expect the secondary to take over.....

 

 

Thanks.