In SSRS, to can use Multiple AND or Multiple OR in IIF expression, you just need to enclose each condition with parenthesis () as the following:
SSRS: Multiple OR in IIF expression
To use Multiple OR in IIF expression in SSRS, you should use the below syntax
=IIF((Condition1) OR
(Condition2) OR
(Condition3), True,False)
In your case, the Multiple OR condition in IIF expression should be
=IIF((Parameters!Name.Value="All") OR
(Parameters!Name.Value="Select Value") OR
(Parameters!Name.Value=""),True,False)
SSRS: Multiple AND in IIF expression
To use Multiple AND in IIF expression in SSRS, you should use the below syntax
=IIF((Condition1) AND
(Condition2) AND
(Condition3), True,False)
Ex: to use Multiple AND condition in IIF expression in SSRS
=IIF((Parameters!Name.Value="All") AND
(Parameters!Name.Value="Select Value") AND
(Parameters!Name.Value=""),True,False)