If the character is Kinematic it's quite trivial in the character's script to do something like:
var starting_position
func _ready():
starting_position= position
func respawn():
position = starting_position
When the scene first loads the starting position of the character is saved in a variable, when the player dies that position is retrieved and set as the current position.
Consider resetting any relevant variables. along the way. Having a dedicated function to handle initialization and recalling it might be helpful depending on complexity