You can only delete an SIP on Dhan right now by following the below steps:
Go to the 'SIP' tab thorugh bottom navigation bar, and then tap on 'All SIPs', you will be able to see all the funds that have existing SIPs.
Click on the fund for which you want to modify your SIP details.
Tap on 'Delete’ to stop all future instalments.
You can re-start your SIP anytime in the future again!