Accidentally contributed to Trad IRA instead of Roth

I accidentally transferred money into Trad IRA instead of Roth. Called, but institution couldn't stop/cancel the transfer. Money has not been allocated. Checked with the institution, it is NOT even IN the IRA account yet.

 

How do I go about moving this back to where it should be: in the Roth?

Recharacterization? Do I need (if any) paperwork? Difficult to do? It's a very small amount. Less than $100. 

thank you