There's many tools you can use to remove and refit these hose clips but here's what i use and the clips are removed and refitted in seconds just with a pair of cheap right angle circlip pliers
throttle body clip 1.JPG
Spot which end is the "open end" of the clip then, whilst squeezing the clip with the pliers like this just lever up the open end of the clip by levering over the pliers and "ping" it's off

throttle body clip 2.JPG

throttle body clip 3.JPG
To reattach the clip just squeeze together the two outside edges until it snaps back into position. All done in seconds