How to change Instagram handle?

Hello,

I have two Instagram handles
1. Varun172
2. Varun.sud

I wish to change varun172 to Varun.sud but since Varun.sud is already taken (belongs to me) Instagram won’t let me do it. If I delete Varun.sud will it be able to change varun172 to varun.sud? I don’t want someone else to take it before I do? Any idea who how much time before Instagram will let me change it after deleting?

Any advice will be really helpful. Thanks

Varun