Looks like “maybe” a 4148 SMD diode.
Remember that correct orientation is important (it only works in one direction).
In the picture, the diode “stripe” (Cathode) should be on the left.
Remove the old one by touch the pads one at a time with the soldering iron and lightly wipe the old pieces off by Sliding the soldering iron off the pad gently. Never push hard on anything. Let the heat do the work.
Never leave the soldering iron on the pad for more than 6 seconds. Let the PCB cool down and try again if t doesn’t work.
Next “tin” the pads with fresh solder.
Hold a piece of “leaded” solder (don’t use lead free) on the pad and then touch the pad with the solder iron for just a moment. This should leave a small amount of solder on the pads to prep for the part. Do this to both of the empty pads. You are ready for the new part.
Using some tweezers, set the diode on the pads in the correct orientation.
Hold the diode in place with the tweezers and touch one pad with the soldering iron so that one side of the diode solders to the pad. It should only take 1-2 seconds max with fresh solder on the pad.
Let go of the diode and then touch the other pad with the soldering iron and it should be in place.
If you make a solder bridge on accident, just wipe the soldering iron across the pads gently and it should correct it’self.