Strictly following the rules of Monopoly will show that just because you have the cash to out-right buy hotels for your properties, you cannot if there are not enough houses in the bank to support an even build (ie, there are less than 12 in the bank for a 3 property street).
Likewise, when tearing-down hotels, there need to be an appropriate number of houses available to support the even tear-down (at least four houses to remove one hotel, and 8 more if you want to remove all of the improvements on a 3 property street).
What happens if you cannot tear-down your hotels because there are fewer than four houses in the bank (or fewer than 12 for the whole street)?
The scenario is not that far-fetched - a property group has been fully improved, some large rent is now due, and the player needs to recoup the sunk cost of their improvements to pay the rent due.
If they cannot tear-down the hotels, they cannot pay the rent. But property cannot be traded between players if improvements are on it.
What is the appropriate resolution to this case?