I'm converting plsql to PostgreSQL how to return raised exception in PostgreSQL

I’m converting plsql to PostgreSQL.
In plsql:

declare
W_USR_EXCE EXCEPTION;
......
raise W_USR_EXCE;

I have converted in PostgreSQL like this

     IF (W_DAY_TOTAL_AMT > W_NEW_LIMIT) THEN
            W_ERR_MSG := 'Exceeds Benificiary Limit';
 RETURN EXCEPTION USING ERRCODE = '50011';

if "if" condition executed am getting "W_ERR_MSG" message along with that i need EXCEPTION to return

but it is not returning any value.
Please help me to solve this error.

>Solution :

Just for reference you can use the below psudo code to raise any error message in POSTGRESQL :

RAISE EXCEPTION ‘Nonexistent ID –> %’, user_id
USING HINT = ‘Please check your user ID’;

follow the link for more details :
https://www.postgresql.org/docs/current/plpgsql-errors-and-messages.html