Optional training, for if you find some time in an "unavailable" day

It would be nice to have an Optional training for an Un-available day.

Basically, if for example i'm unavailable on Monday and Tuesday, but i do find an hour all of a sudden, in stead of changing the availability for the day, it could have the an option that says:

1. If you find an hour

2. Chose a training of x/y/z (aka endurance/strength, depending on overall training plan / goal.

3. Please chose one of the following trainings (which have maybe different duration/ type of training), from the overall training data base.

Ideally this training will only change the remainder of the week in intensity / not in removing a training... as i like to plan out the week, have my days ready for training (aka this week i did a heavy long training on Tuesday, did a very very mild commute training on Wednesday, by uploading my Wednesday training, my Thursday training was removed, however that would be my last available day till like Monday, so ideally it would still remaining, but lower in intensity/duration.