Have you determined if it really needs to be removed? Normally you can apply the new layer of sealant over the old layer. Try this - I would thoroughly power wash the area first. Then apply sealant to a smaller section in full sunlight. Check the after after six weeks. In some situations, if the original layer of sealant has become brittle, the sealant will form a whitish color. If this is the case, then you may need to use a sealant stripper to remove the original layer or use a CCS Fusion seal. In that case, you might want to contact a professional.