Hello Kathleen,
Your client will need to use our bridging tool which will be available in April. It will involve having to get a secondary account that is set up as GBP - we are currently in negotiations with sales for there to be a fixed price for this.
There will of course be further information on this released closer to April - but for now know that we do have a plan for customers like your client so you do not need to worry.
Thank you,
Talia