For lollipop versions, Goto
Settings -> Sim Cards -> Call settings -> Phone account settings -> Make calls with ->
Under this you will have three options
Ask First option from that menu and when you call someone from the contacts, you will be shown the Sim 1 and Sim 2 option. Select the
Remember SIM for number checkbox and select the sim card you want to associate the contact to. The next time you call that contact it will automatically call using the sim you configured as default(It wont show you the sim selection iption). Do remember that you can always switch the sim cards while connecting to call by clicking
Change sim option.
First you need to enable this feature in
Dual SIM settings -> Call settings -> Automatic SIM selection.
The setting for Dual SIM settings->Call settings->Making calls should be set as “Ask every time I make a call”.
Dual SIM settings -> Call settings -> Making calls.
Remember SIM for number and then select either SIM 1 or SIM 2 to make the call. The next time you make a call to that contact it will automatically call using the sim you configured as default based on the call history.