water pump belt replacement

I have the "special water pump wrench" and am getting ready to replace my water pump and it's seal after it began hemorrhaging fluid (I assume the o-ring seal is broken).
I need to replace the belt, but it looks like an awfully tight squeeze around the tensioner.
Is there a trick to doing this?
Please help before I reach a point of no return.
Thanks to all...this site has been a tremendous help.
Digby

use an open ended wrench instead of a socket wrench on the tensioner

use an open ended wrench instead of a socket wrench on the tensioner

Dwalmop, are you saying I have to remove the tensioner arm from the vehicle?
Or do I somehow slide the loose belt around the side of it?
digby

I managed to get the belt around my tensioner, but others have just removed it. A couple of bolts I think?