Update the Transit Key Strength to 2048 from 4096

We have some keys in our Transit engine with key strength as 4096, we would like to update the strength to 2048 with an aim to reduce the size of the Cipher Text. I have been trying with the REST interface with body as { “type”: “rsa-2048” }, though it’s returning 204 subsequent read key still shows 4096. Is the Key type read only? Can we not rotate the key and then decrease the size of the Key Strength.