Would it be possible to bend time if one were able to manipulate gravity?

It would not be possible to bend time even if you could manipulate gravity because gravity relies on the earths magnetic core, as gravity dose on any planet. If it were possible to manipulate gravity you could in theory change the mass of an object, but gravity has no effect on time. Time is something humans you to measure events and the duration between them. Time itself is not a thing, nor is it an event, in itself not measurable thus making time travel or the bending of time not possible.