How to perform a constrast in R for a cox proportional hazards model

I have the following model fit:

Call:
coxph(formula = surv ~ data$Arm * x) coef exp(coef) se(coef) z p data$ArmLevel1                   0.062322      1.06  0.70338  0.0886 0.93
covariate1                    -0.000495      1.00  0.00710 -0.0697 0.94
data\$ArmLevel1:covariate1       0.003183      1.00  0.00857  0.3714 0.71


What's the easiest way to test that covariate1 is significant controlling for Arm? Thus I want to use this model object to test that covariate1 is significant given that ArmLevel=0 and that ArmLevel =1?

If there's a way to look at this both sliced (thus both p-values) and pooled, that would be great!

Thanks!