cave in

verb

To collapse inward or downward.
“The roof caved in under the weight of the snow.”
“It was to assist in the filling-in of the tunnel on the disused Patricroft-Clifton Junction line, which was the scene of a disaster in 1953 when part, below some houses in Swinton, caved in.”
To cause to collapse inward or downward.
“He caved in the side of the barrel with a single well-placed kick.”
To relent; to grant approval against one's initial will.
“After he asked me a few times, I finally caved in and had a slice of cake.”
“Eventually the NUR overplayed its hands with an all-out strike. And when Peter Parker, the then-chairman of BR, who was well regarded among his staff, called their bluff by threatening to close down the entire network, they caved in.”