For Intra Cell Handover, do we need any interface like X2?

Mobility
1

Hi Experts.
For Intra Cell Handover, do we need any interface like X2?
Or is it just a feature of eNB?

Any insight is welcome.

2

It’s handover on same cell by RRC connection reconfiguration.
Seen same with TTI bundling.

3

Anything which requires reconfiguration of physical resources, intra cell handover can be performed.

4

Security key change.

5

Yes, that is PDCP reconfiguration, right?