Switch (Standby /Read-Only) DB to be read and Write.

Hi

I'm trying to do Sharepoint DR with Log Shipping and every thing configured except one thing which is switch the WSS_Content (Standby /Read-Only) DB to be ready and Write. 

I tried from GUI or ALTER DATABASE [WSS_Content] SET READ_WRITE WITH NO_WAIT

but I received the below error: 

Database WSS_Content is in Warm Standby 

any help.