Link parent and child record using dialog window

[NAIDILE S]

Hi All!
how can i link the parent and child record with the help of UI action?
here i have SIR, where INC is created from SIR. so i will get a dialog window to fill the INC. INC is getting created, but not getting linked to SIR.
ON SIR form there is incident ref field so that the related INC is shown there.

so can any  one help one this

Thank you