how to merge two forums threads,

[bluedevil]

hello, i want to merge the threads of one forum to another forum , i mean i have threads in forum A and forum B , i want to move threads of forum b to forum A, so that i make only one forum contain both forum threads,, in same category,
anyone know how to move the whole forum threads to another,

 

[iFlames]

Go To ACP --> Threads & Posts --> Move