Can I respec my Ryder?

Yes, you are able to do this shortly after completing the prologue. This guide explains how to do this:

In order to respec your character, you're going to need to acquire the Tempest. This will happen after you've finished your missions on Habitat 7 and the Nexus in the game's prologue.

Once you've acquired your ship, make your way down to Deck 3. You can do this by climbing down either of the ladders right outside the bridge area, which will lead to a lower level, or use the lift in the back of the cargo bay to head down.

Once you climb down either of the ladders, search for the Med Bay room. When facing the Pathfinder's Quarters, which is the room between the two ladders, it should be the bottom right door.

Once you're in the Med Bay, turn left. Usually, Lexi is standing and working in the side of the area. To the left of her is the Respec Station.

It's worth noting that these increase in cost each time. From the same site:

It will cost you a mere 20 credits to do the first respec; any future respecs will cost you a significantly larger amount of 500 credits. This rises precipitously each time you respec per save file, so do so sparingly.

Yes you can, for a fee. In the medical bay aboard the Tempest on the screen to the left as you enter there is an option to reset any squad member's abilities, including your own.

Note: once you have the secret tech ability that you get by helping Peebee with her quest, resetting your skills during a NewGame+ will remove this ability until you relearn it later in the story.

This will pop up a prompt, stating the amount you will be charged for this reset.