If you mean Apple ID accounts, you can't. They cannot be merged and you should have insisted Verizon use your old ID. Depending upon exactly how you want to do things there are several ways of getting by using two accounts, of if you have not used your new account yet to buy anything I'd just abandon it and use the old account. If you must use both then Family Sharing may be the best way to do this unless it presents other issues:
Family Sharing - https://support.apple.com/HT201060 - "Family Sharing makes it easy for up to six people [different Apple IDs] in your family to share each other’s iTunes, iBooks, and App Store purchases without sharing accounts. Pay for family purchases with the same credit card and approve kids’ spending right from a parent’s device. And share photos, a family calendar, and more to help keep everyone connected."