Sprint said late Monday that SoftBank had waived provisions of its deal with Sprint that will allow Sprint to talk with Dish.
SoftBank currently has a $20.1 billion deal with Sprint to buy 70 per cent of the company. Dish last month offered $25.5 billion for the whole company.
Softbank says it brings expertise and cash to Sprint. It says it still wants to close its deal by July 1.
Many Wall Street analysts view Dish's bid as superior but risky, as it will result in a combined company with high debt.