Relevel function in R for GLM

We (the community) can give you better help with FAQ: What's a reproducible example (`reprex`) and how do I do one? which would include the call of the model glm(y ~ x, data = dat, family = "poisson") [whatever] and some data of the same form, which doesn't have to be real.

Without that to work with, the answers you can expect will probably be too abstract to be as useful as they could.