Rotating an old fitting

I'm looking to move a gas line from one side of the basement to the other. To do so, I need to rotate one of the fittings by 90° then run the pipe from there. I've been assuming that I will need to remove the fitting, re-dope, then re-install (probably just get a new fitting to be safe). The problem is that I'm not sure if I have the clearance to back off the fitting without getting stuck on the water pipe next to it, meaning I may have to R&R additional fittings upstream. My question is whether I can just tighten it 1/4 turn without removing it, or is that likely to cause a leak? I'm assuming I will have to R&R, but I don't want to make extra work for myself if it's standard practice to just tighten an old fitting.

 

Unfortunately, you would have to loosen the elbow to rotate 1/4 turn. So could you rotate 3/4 turn and clear the pipes next to the elbow. I am not a pro.

 

The fitting I'm trying to rotate is the the one circled below in red, I'd be rotating it 90° clockwise, which should be tightening it. The vertical pipe in the top left of the photo will be removed and once the fitting is rotated, will be replaced with a pipe shown in blue that goes to the wall on the right.

 

I had not pictured it right. I would think that if you can rotate 1/4 turn CW, you would be good.

 

Is it possible to rotate it, put a plug in the open side and test it for leaks before you go any further?