Updating Bill Amount in One-to-Many Relationship: Handling Removal of Bill Lines

[zerosix]

I have two entities with a one-to-many relationship (bill and bill lines). I can update the bill amount after a bill line update using a custom script formula before save custom script. However, I'm unsure how to apply a similar process when bill lines are removed. How can I handle this?
NB: i am not using the sales pack

[yuri]

I'm not sure there's a solution w/o advanced pack or w/o coding.

[rabii]

I have two entities with a one-to-many relationship (bill and bill lines). I can update the bill amount after a bill line update using a custom script formula before save custom script. However, I'm unsure how to apply a similar process when bill lines are removed. How can I handle this?
NB: i am not using the sales pack

You need a afterRemove hook. https://docs.espocrm.com/development/hooks/