There are two handle styles for the Kenmore Ultra Fresh refrigerators available around the time of the model, 106.55539400. On one handle style, you need to remove trim pieces to access the part of the handle where it is attached to the door of the refrigerator. In turn, apply firm pressure on each trim piece and push it away from the handle. (Push the top trim piece up and the bottom one down.) For the other style, the handle locks into shoulder pieces that are attached to the door. Again use firm pressure on the handle; hold it in the middle of the handle. Push the handle up until it clears these shoulders. Then determine the correct screwdriver tip to use to tighten these screws. See page 7 of the manual, https://www.searspartsdirect.com/manual/25o0qstrl6-000582/kenmore-10655539400-side-by-side-refrigerator
, for pictures of these handles. On some more recent refrigerators, you will need to use an Allan wrench to tighten set screws to the hardware shoulders on the door. There will be a small opening on either end of the handle for the Allen wrench to be pushed into contact with the screw.
Please add a comment with the model of your refrigerator for specifics about the handle for your unit. I hope this helps.