Frontier Airlines’ amended lease at Denver International Airport, which allows it to reduce its gates to eight from 14, won approval Monday from the City Council in a block vote.

The airline, which has been “right-sizing” its DIA operations, will return the six gates by January in exchange for a $3 million cut in its annual gate-rental fees. It now will pay $27.4 million a year while maintaining or even growing its existing service out of DIA, Frontier says.

The airport plans to use the freed-up gates in concourse A to move Delta Airlines from concourse C by late spring. DIA also plans some improvements to the concourses as the shifts occur.