On one of my kilts, according to my estimation worn around 500 times and still in excellent condition, the strap on the left hip, securing the inner apron to the outer via the buckle, is wearing thin and coming somewhat loose. By all accounts, this seems a relatively trivial matter but my manual capabilities are extremely limited, extending scarcely beyond flipping a light switch, so to me this poses an acute problem.

Is there a simple way such a strap can be repaired or replaced?

Since the strap is rooted within the sown area of the under apron, it would apparently require opening that section, removing the ageing strap and inserting a new one, followed by securing the sown area.

If this requires more or less professional attention I would be grateful to know of such persons or agents who live in the greater Philadelphia /northern Delaware area, to where we have moved only recently.