Not able to edit query under Source Data in Analysis service

 Hi All,

Not able to edit query under Source Data in Analysis service 

In sql its easy to write a where statement but in power query we had to perform the below steps 

Click on Source Data under properties in AS Table name.  

Then Click on Design 

Then Apply filter and the query looks like below 

let 
Source = #"SQL/c-nt", 
SSOT_DM_FactSales = Source{[Schema="Sm="FSs"]}[Data], 
#"Filtered Rows" = Table.SelectRows(SSOT_DM_FSs, each Date.IsInPreviousYear([Date_SK])) 
in 
#"Filtered Rows"