Unfortunately no. If you have created an offer and it subsequently transpires that the wrong tax type was selected, this can no longer be changed after creation. In this case, you would either have to create a new offer with the same parameters or copy the existing offer and change the tax type in the copy. By using the copy function, all settings of the offer are copied one-to-one and a new creation is simplified.
Please note that changing a copied offer has no effect on the existing offer. Neither the offer ID nor the customers who purchased the original offer will be copied. The copy function only duplicates the parameters. In this sense, a completely new offer is created.