The cell (building block) like the phase shifter is defined by a foundry (in a PDK), you can not change which parameters is has (unless you define your own building block, which may require advanced knowledge of a technology/process). You can change, however, how you connect to a building block.
For an example on connecting (building blocks) see https://nazca-design.org/connecting-to-a-building-block/
For an interconnect taper use e.g. demofab.deep.taper(length=50, width2=3.0).put(...)
A taper has keywords width1 and width2, but if not provided it defaults to the interconnect width.