23 Va. Admin. Code § 10-210-10 - Adjustments, Replacements and Warranties.

When any taxable article is returned to the dealer for adjustment, replacement or exchange and the consumer is given a new article free or at a reduced price under a warranty or guarantee, the sales or use tax must be computed on the actual additional amount, if any, paid to the dealer for the new article.

For articles returned for cash or credit, see 23VAC10-210-3080.