Those set of commands didn't seem to work. However, with a little digging and reading I found this set of command did work. 

%r
# Load Sparklyr library
library(sparklyr)

# Connect to the cluster using a service principal
sc <- spark_connect(method = "databricks")

# Set the database where the table is located
tbl_change_db <- "xxx_mydata"

# Use spark_read_table() function to read the table
data_tbl <- spark_read_table(sc, "mydata_etl")