Your question is not clear. In GAMMADIST, alpha is the shape parameter,
which is entirely standard. beta is the scale parameter, which is less
standard. Many sources omit the scale parameter all together, which is
equivalent to beta=1. Some sources use a rate parameter, which is 1/beta.
If you want to use a rate parameter, simply use
=GAMMADIST(x,alpha,1/rate,cumulative)
