Can someone tell me how to convert my 2009 Reba Teams from 100mm to 120mm?

Something about removing a spacer???

It's a simple job, and SRAM/Rock Shox have a handy set of video's on their website that show you exactly how to do it.

Tis easy… peterpoddy has a good guide on it.

Here's PP's guide:
here

Just don't do what I did and whinge about it not being right, not knowing that the spacers look different from year to year. In 2009 it looks kinda like a plastic cotton-reel and not a plastic C-shaped thing. It won't clip off like the one pictured, you have to slide it off with everything else and then put all that back in the correct order.

Edit: and it helps the hammering if you stick a 10mm socket on the nut on the -ve valve. Mine took a lot of violence before they let go.

thats great, cheers!