How to transfer itc from one state to another state by one person having two different gstins

Assuming your contractor is having GST registered in both state A.P. and Telangana

Since he will have to send tipper from A.P. to Telangana, he will have to show outward supply (sale) in A.P. state and purchase in Telangana state and then he can claim ITC in Telangana.

If tipper is directly supplied to Telangana, then contractor should have provided Telangana GST and supplier should have charges IGST, in such case there would have been no question of ITC transfer.

To best of my knowledge, it should be shown as sale and purchase in respective state and ITC shall be transferred

Do not agree with Mr. Sahil here. 

There is no issues in ITC being claimed in A.P. Circular 21/2017 provides that movement of tipper like vehicles can be sent under DC + EWB without raising invoices. Upon purchase bill to ship to can be used to ensure credit moves to the correct State.