Need advice on build out of single tenant building

[John McKee]

I have a standalone former drive thru bank that is now a vet clinic.  The vet clinic wants to expand the building at their cost into the drive thru area as they don't need the drive thru.  Should I charge them more rent to take up more space?   My thought is that the the drive thru is the most valuable part of this property in case I need to release it.