Recession (and the related risks and uncertainties) goes both ways.

If the real estate marked drops significantly and doesn't recover quickly, you will have overpaid if you buy at the agreed price. It would indeed be reasonable to ask for a price reduction and cancel the deal if you don't get one.

If the government decides to counter the economic recession by [emitting more money](https://en.wikipedia.org/wiki/Stagflation) (thanks for the link, @Underminer), real estate prices will keep raising due to inflation. It would then be reasonable for the seller to raise the price now, and cancel the deal if you don't agree.

Unless the future is known *right now* with a reasonable degree of certainty, changing the price either way is groundless. Indeed, if the price of the property has already changed (as the property valuation from your bank shows), it's only fair to review the deal to the actual price.