Method 1 (1 soldering irons)

Add fresh solder to both ends of the diode and quickly move the soldering iron back and forth between both ends of the diode until the diode is released from the pads.

Method 2 (2 soldering irons) [Photo 2]

Heat up both soldering irons.

Add fresh solder to both ends of the diode. (Photo 1)

Hold iron onto the end of the diode and feed solder onto the board right at the tip of the soldering iron.

Hold soldering irons on both ends of the diode and lift the diode off of the circuit board once the solder melts. (Photo 2)

Repeat the above steps for the remaining diodes.